The 164th Manchester derby was certainly one to remember as United opened up a six-point lead at the top of the Premier League with a last-gasp victory at the Etihad.
A Wayne Rooney first-half brace had given the Red Devils a daunting lead but City came out fighting in the second half and managed to pull it back with goals from Yaya Toure and Pablo Zabaleta.
However, United were to have the last laugh as they silenced their noisy neighbours in the 92nd minute when Robin van Persie's free kick took a slight touch off the cowering Samir Nasri to beat Joe Hart and send the visiting fans into raptures.
Read how it all the drama unfolded in our minute-by-minute updates below.
Morning folks! So we're two-and-a-half hours away from the biggest game of the Premier League season so far. Will it be one to remember?
We've got plenty of build-up on today's match and it can all be found on the game's homepage right here.
In our preview, Barney Corkhill has plumped for a 3-2 City win. Personally, I think it will be a much cagier affair with perhaps just one or two goals. Read Barney's full preview by clicking here.
There have been some classic Manchester derbies over the years and a couple of the greats have come in the last few years. Remember in 2009 when Michael Owen scored the winner for United in about the 98th minute? Or last season when City came to Old Trafford and annihilated Sir Alex Ferguson's men 6-1? My colleague Jack Prescott compiled a round-up of five classic Manchester derbies, with accompanying video, that can be found by clicking here.
Speaking of Owen, the former United striker, who now plies his trade at Stoke City, has said that the Red Devils will win today.
City skipper Vincent Kompany is clearly excited. He tweeted this 40 minutes ago: "It's derby day! #MCFC" You may remember that the Belgian scored the one and only goal the last time these two met at the end of April that effectively handed City the Premier League title.
A hint on City's team news perhaps? Independent journalist Jack Pitt-Brooke has just tweeted this: "So apparently Balotelli will start ahead of Tevez. I'd always go for Tevez in a big game, but I'm boring.
"Maybe Tevez is exhausted from trying to carry Edin Dzeko, Samir Nasri, Scott Sinclair, Javi Garcia and the rest on Tuesday night."
"Maybe Tevez is exhausted from trying to carry Edin Dzeko, Samir Nasri, Scott Sinclair, Javi Garcia and the rest on Tuesday night."
Let's take a look at the overall head-to-head between these two sides over the years:
Total Matches: 139
City wins: 39
United wins: 55
Draws: 45
Total Matches: 139
City wins: 39
United wins: 55
Draws: 45
Today's meeting is the 31st between the two sides in the Premier League and as mentioned earlier it was City who did the double last season.
Of the 30 previous PL meetings, United have won 17, City 7 and there have been 7 draws. There's a lot of sevens there, does that mean it's going to be 7-7 today?
Although City are trailing United in the table, Roberto Mancini's men are the only unbeaten side in the league and have a run that stretches back through last season of 21 games without a league defeat. Avoiding a loss today would see the club equal their all-time top-flight 22-match streak set from 1936 to 1937.
Looking ahead to the lineups today, City are said to be without Aleksandar Kolarov, Jack Rodwell and Micah Richards. James Milner and Gael Clichy should be fit while playmaker David Silva is expected to feature despite missing Wednesday's Champions League loss to Borussia Dortmund.
United, meanwhile, are without the rapid wing duo of Nani and Antonio Valencia, with big names Shinji Kagawa and Nemanja Vidic still sidelined. Improved performer Anderson is out of action for three weeks after suffering a hamstring strain while Tom Cleverley is facing a race against time to be fit for today's clash.
One thing we certainly don't want today is trouble and there's plenty of police on the ground to prevent any skirmishes says MEN journalist Rob Dawson on Twitter.
On a brief side note, if you like your La Liga then you can follow Matt Law's live updates of Levante vs. Real Mallorca (it's currently 0-0) by clicking here.
City are trying to create a baby-blue backdrop as the teams come out. The club have put City flags on every seat for the crowd to wave when the sides exit the tunnel.
A United victory today would certainly buck the trend as City have won 29 of their 32 home league games since Everton picked up a 2-1 win at the Etihad on 20 December 2010. Scary.
From a betting point of view, City are favourites at 5/4 with United at 11/5 and the draw at 12/5. I like the odds of a draw there, I think.
If United are to upset the odds today then they will need to shore up their leaky defence. Former United stopper Edwin van der Sar knows this is key, he's just tweeted: "Will be watching from home and wishing the lads all the best as they need a convincing performance - starting from the back!"
The Manchester derby is undoubtedly the game of the day but there's two other top-flight matches also taking place. At 3pm, Everton welcome Spurs to Goodison for a tasty affair. Victory for the Toffees would see them leapfrog Spurs and go into the top four. An hour later at 4pm Liverpool go to West Ham without their one-and-only striker Luis Suarez, who is suspended, with Jonjo Shelvey touted as the name who will lead the line.
City's goal difference, that is one better than United's at +17, means that any win for the Blues today will see them oust United atop the Premier League.
Looking at the form table, United are top with five wins from six while City sit fourth with 12 points from a possible 18.
City's second successive group exit from the Champions League in midweek was a major disappointment but Kompany, speaking in the City programme, said this: "Everyone in the football world knows City are destined for greatness in Champions League and if they don't they would be ignoring the truth."
Being in England, it wouldn't be right not to have a weather update! It's a dry but brisk day in the North West.
United will look to Robin van Persie for goals this afternoon and City captain Kompany isn't fazed by facing the Dutchman. He's said that coming up against the world's best is a great challenge.
You may have noticed the picture above of Ferguson and Mancini squaring up earlier this year and the mind games have been plentiful ahead of today's match. Both managers have said that the other has the upper hand in the title race while Ferguson made journalists chuckle at his press conference on Friday. The Glaswegian suggested that if United had been awarded as many penalties at home as City recently then there would be a House of Commons inquiry!
United frontman Wayne Rooney has said that wide areas will be key for United today and that seems a strange thing to say considering the Red Devils' strongest widemen, Nani and Valencia, are missing.
CELEBRITY SPOT! Hollywood star Tom Cruise is reportedly at today's game.
The City team have just arrived at the Etihad and Mario Balotelli, who tends to thrive on these big occasions, is sporting some ridiculous bright pink headphones. Not like him to make a scene.
Former United keeper Peter Schmeichel has been speaking to BBC Radio 5Live's Sportsweek programme and the Dane says that a draw would be a great result for United.
BREAKING TEAM NEWS! Mario Balotelli starts for City!
Hart; Zabaleta, Kompany, Nastasic, Clichy; Yaya Toure, Barry; Nasri, Silva; Aguero, Balotelli
The controversial Italian accompanies Sergio Aguero up front for the hosts ahead of Carlos Tevez and Edin Dzeko.
Balotelli, remember, scored twice in that famous 1-6 victory for City at Old Trafford a little over a year ago. 'Why always me?' said the famous undershirt he revealed. Will the 22-year-old be writing the headlines again?
Balotelli's inclusion for Tevez is one of five changes for Mancini, with Pablo Zabaleta, Gael Clichy, Matija Nastasic and Aguero in for Maicon, Kolarov, Joleon Lescott and Edin Dzeko
The United team is in! Antonio Valencia is fit to start!
De Gea; Rafael, Ferdinand, Evans, Evra; Valencia, Carrick, Cleverley, Young; Rooney; Van Persie
Valencia is a surprise inclusion on the right then, with Ashley Young on the other wing. Tom Cleverley passes a late fitness test to start alongside Michael Carrick in the middle, with Rooney just behind Robin van Persie up top.
Pantilimon, Maicon, Kolo Toure, Garcia, Tevez, Dzeko, Lescott
I predicted earlier in this commentary that this game would lack goals but with Fergie choosing to play two wingers, Rooney and RVP and Mancini opting for Balotelli surely this game has goals in it?
We're still waiting on the United bench but in the meantime you can click here for a fuller look at the starting lineups.
Johnstone, Jones, Giggs, Smalling, Hernandez, Welbeck, Scholes
No Anders Lindegaard for United at all then. The Red Devils are also without Darren Fletcher.
Tom Cruise is lapping up the attention. talkSPORT commentator Stan Collymore tweets: "Tom Cruise signing autographs by the tunnel!"
Both managers need big performances from their less-experienced centre-backs. For United, Jonny Evans received plenty of criticism for his performance in last week's loss at Reading while Matija Nastasic needs to show he can handle the big stage.
Half an hour until the off.
The two sides are warming up and the excitement is building. I'm going to change my prediction and plump for a 2-1 United win.
Tom Cruise isn't letting the fans down by sporting some 'Top Gun' style sunglasses. Robert Duvall is also at the Etihad today.
One thing I think will definitely not happen today is a clean sheet! The front four of both sides are particularly menacing.
Cruise and Duvall have been speaking to Sky Sports News reporter Geoff Shreeves. Cruise says he's been following football "since the 80s" but that this is his first match in England.
Duvall says he's followed the World Cup for many years while Cruise is now promoting his new film 'Jack Reacher'.
Cruise is known to be friends with David Beckham and he says that Becks is gutted not to be there: "He wishes he was here. He is in LA ... he is jealous I am here." Both men add that they can't call it and remain horribly neutral.
10 minutes until kickoff.
There are only two unbeaten clubs in Europe's top leagues - City and guess who? Yep, Barcelona.
We now know the reason why Anders Lindegaard is strangely absent today. Press Association journalist Simon Stone tweets: "Lindegaard's wife has gone into labour, hence his absence."
Mancini tells Sky Sports News that having a good balance of attack and defence is key to victory. Fergie, meanwhile, says that United need to play their way and avoid handing City too much possession.
The two sides are ready and waiting in the tunnel, here we go.
It's a predictably electric atmosphere inside the Etihad. The Premier League's biggest game of the season is about to begin.
An extremely amicable welcome for Ferguson from Mancini. No handbags. Yet.
United get us underway!
A wasteful start to the match by Evra as the Frenchman lumps aimlessly upfield.
United are pressing the ball nice and high early on, forcing City to play the ball quickly. That's a clear instruction from Ferguson as he doesn't want the hosts having too much of the ball.
Rooney is certainly up for this! He's just brought down Silva and Toure with a pair of late challenges and is lucky to escape a booking.
Those tackles from Rooney mean that he is already getting plenty of boos.
And now Ferdinand comes across Aguero and City have a free kick 35 yards out, left of centre.
Balotelli fires low and De Gea parries wide although it looks as if that wasn't going to hit the target. Corner for City.
Balotelli whips it in and that's a superb defensive header away at the near post by Van Persie.
Almost all of the football is being played in the United half at the moment although we're still to see a goalscoring opportunity.
Young isn't happy after a challenge on Balotelli. The United winger looks really fired up.
CHANCE! Silva clips in a ball behind for Clichy and the Frenchman does well to keep it and Balotelli has a tough chance on the volley at the back post that he blazes miles over.
Almost a hairy moment for De Gea as he fumbles a corner under no pressure. Luckily for the Spaniard there's no City player close by to nab the ball.
Nasty, nasty lunge from Balotelli on Evans and referee Martin Atkinson again decides against a booking. Lenience is definitely the order of the day it seems.
Aguero's first touch lets him down when played through by Balotelli.
GOAL! UNITED TAKE THE LEAD! ROONEY!
It's completely against the run of play as Young breaks clear down the left and feeds inside to the Englishman. His first touch is good and he then shoots scruffily back across goal and it dribbles into the corner past a wrongfooted Hart in goal.
What a suckerpunch for City, who had started on the front foot and looked the far more likely side to score. That attack was perhaps just the third or fourth time United had ventured into the final third.
City are making an early change as Kolo Toure is stripped and ready.
Blimey, City skipper Kompany is the man to be removed and that has to be an injury. Sky Sports News reporter Geoff Shreeves says that it could be a groin problem. The Belgian is visibly angry at having to come off in such a big game.
Almost a chance of a second for United as Van Persie clips a brilliant ball over the top for Young but Hart is quick to react and clear the danger. The visitors continue to press as RVP receives on the left but his cross can't pick out a red shirt.
CHANCE! Aguero somehow manages to keep the ball and plough his way through several challenges before being presented with space to shoot. The Argentinian's sidefooted finish doesn't have enough on it though and De Gea dives low to his left and holds on.
Valencia wins a corner for United and Van Persie swings over to an unmarked Carrick at the near post but the Englishman can't get enough on his flick and City clear.
City look to break through Yaya Toure and the Ivorian bustles his way through a pair of challenges before going to ground. Atkinson waves away the appeals for a free kick.
GOAL! UNITED 2-0! ROONEY AGAIN!
Far, far too easy for the visitors. Valencia passes to Rafael on the overlap and the Brazilian cuts back for the onrushing Rooney to tuck home low to Hart's right.
Nasty Kolo challenge from behind on Van Persie gives United the opportunity to slow the pace down a touch.
For future reference, I will be referring to the Toure brothers as Kolo and Yaya for the rest of the match!
Valencia is picked out superbly on the right and the winger almost finds Rooney with what would have been a carbon-copy of the second goal. The ball is cleared to Cleverley but his shot under challenge is high, wide and not so handsome.
City have a chance to swing in a dangerous ball but Silva's delivery is too floaty and De Gea claims under no pressure.
Rooney's brace today means that the Englishman has now scored 10 goals in Manchester derbies.
City return to their patient style of play and Zabaleta wins a corner that yet again Van Persie does well to head clear. The Dutchman's header goes straight to Nasri and his centre looks good but is well punched clear by De Gea. You feel that City really need a goal before the interval.
Dangerous play from Young on the edge of his own box but he manages to win a free kick as Zabaleta looked to steal the ball and break into the area.
United go in search of a third as Rooney nicks the ball from Yaya and passes to Van Persie who runs at the City defence but has his shot blocked.
CHANCE! Silva passes in to Balotelli with his back to goal and the Italian neatly lays off for Barry on the edge of the area but he drags his shot well wide of the post.
City appeal for a penalty as Balotelli looks for Aguero with a through ball and the Argentine goes down when jostling with Ferdinand. Atkinson says nothing doing and rightly so, shoulder-to-shoulder.
Two minutes added on at the end of the first half.
Strange decision from Hart to come and clear a ball near the touchline and the England number one slices out of play for a United throw-in near the corner flag.
City 0-2 United
An absolute mountain of a task for City to prevent them losing their unbeaten record then. The Champions began by far the best team but were hit by some neat United counter-attacking and then some slack marking, with Rooney taking advantage on both occasions.
If you've only just joined us and don't want to wade through the below updates, you can read our concise half-time report, including full-size images, by clicking here.
Surely Mancini will have to think about bringing on Carlos Tevez soon and then super-sub Edin Dzeko?
Many on Twitter are asking why Mancini opted for Kolo ahead of Lescott to replace Kompany. Does seem a strange move by the Italian.
The minute that included United's first goal has two extremely good pieces of play from both teams. First, City almost presented an opportunity for Aguero with some slick interplay but then United showed how to counter attack brilliantly. Young's flick-on to RVP was accurate and then the Dutchman's lay-off with his chest very clever. Rooney's first two touches before the scuffed finish were also of the highest order.
Doesn't look like City are making any changes. Remember, Kompany has already had to go off because of injury.
City get the second half underway.
The hosts win an early corner but yet again Van Persie clears the danger at the near post.
Silva cleverly flicks into Aguero but the Argentinian's deep cross is too long for all the City players in the area. Encouraging start to the half for Mancini's men.
Ferdinand is on his knees with an ankle injury but it's not the Englishman who's coming off. Smalling in fact takes the place of Evans who is reportedly carrying an injury.
Mancini hasn't taken long to play the Tevez card and I expect it to be Balotelli to be removed.
As expected, the Italian is taken off and his petulant nature takes him straight down the tunnel.
Tevez instantly gets in amongst the action but his through ball is straight to the offside duo of Silva and Aguero.
Nasri receives a booking for seemingly swearing at referee Atkinson. Naughty.
Nastisic is down as if he's been shot after a tap on the ankle from Van Persie. City haven't got the time to waste!
Strange decision from Atkinson to award a free kick to the Reds when Young seemed to haul down Zabaleta, not the other way round.
SHOT! Aguero is afforded some space outside the area and he tries to bend it in to the far corner but that was never troubling De Gea.
Nasri is set free down the right and the Frenchman's cross looks destined to pick out Aguero at the back post but for a superb last-ditch challenge from Ferdinand.
OFF THE POST! Oh so close to brilliance from Van Persie! He cuts back on to his weaker right foot and curls a beauty past Hart that comes off the inside of the post. Young follows up the rebound but is given offside. Replays, however, show that the winger was just on!
GOAL! CITY PULL ONE BACK! YAYA!
City are right back in this! Tevez is denied brilliantly by De Gea and the Spanish stopper then does even better to keep out Silva's rebound. The ball finds Tevez again and after a bit of penalty-box pinball the Argentinian picks out Yaya who strokes the ball into the far corner.
City almost work a clever free kick after a rash challenge from Ferdinand but then United storm up the other end with Rooney. The Englishman goes down under challenge from the back-tracking Aguero but Atkinson isn't interested.
The atmosphere is now rocking inside the Etihad and United have a penalty appeal turned down as Evra seems to be felled by Kolo.
Replays show that Evra was clearly tripped by Kolo and also that Smalling stopped the ball with his hand on the edge of the area minutes earlier. Not a great couple of minutes for Mr. Atkinson.
In amongst all the drama, Ferdinand was cautioned for that earlier tackle.
CHANCE! Ferdinand loses possession and Aguero frees Tevez but Evra gets back to just about prevent a clean shot getting away without committing a foul. Touch and go, that.
CHANCE! Rooney's vicious corner reaches an unmarked Evra but the full-back can't make a clean connection as he shoulders it way over.
Smalling has words with De Gea after the Spanish stopper doesn't come off his line to clear the danger. Nerves are jangling.
Zabaleta fumes as Atkinson fails to award a free kick and now Mancini is also angry with the referee as he fails to play advantage after Yaya did brilliantly to evade a couple of lunges. Atkinson seemed to stop the play to award Rooney a yellow card.
Kolo lunges to try and prod it in at the back post but the Ivorian was offside when the ball was flicked on.
The bookings are coming thick and fast now as Yaya swipes at Cleverley when the ball was long gone. City's goalscorer seems to have come out worst though as he is still down injured.
United have a sustained couple of minutes of pressure but it ends when Valencia overhits his slide-rule pass to Van Persie.
Balotelli has returned to the City dugout after having his tantrum I assume.
CHANCE! United break and Rooney reverses to Cleverley to cross for Van Persie but the Dutchman can't quite work his neck muscles to divert it home.
OFF THE BAR! Aguero finds Silva and the Spaniard feints in the box to open up a shooting opportunity that De Gea shoulders onto the crossbar and out for a corner.
Rooney is furious with Atkinson after seemingly being brought down by Zabaleta on the edge of the area.
Into the final 10 minutes or so and there's without doubt the possibility of a fourth goal in this one. It truly could go either way.
Nasri escapes the challenge of Cleverley with a neat fleet of foot but then tries one trick too many and loses possession.
SHOT! City break quickly with Nasri down the right and the Frenchman picks out Tevez but his shot on the turn is too high. Would've been some goal if he'd manage to get that on target.
Final change for City as super-sub Dzeko replaces Yaya while Valencia is removed for Phil Jones for United.
Clichy picks out Dzeko with a ranging pass but the Bosnian is denied a shot at goal by Smalling, who has been very impressive since coming on.
GOAL! CITY EQUALISE! ZABALETA!
The home side win a corner and for the umpteenth time it's cleared by Van Persie at the near post. This time, however, the Dutchman's clearance finds Zabaleta on the edge of the area and he rifles it low into the corner past a helpless De Gea.
United make their final change with Danny Welbeck coming on for Cleverley. Are we going to see a winner?!
Yellow card for Tevez because of the Argentine's angry reaction to being penalised for a block on Rafael.
SAVES! Evra gives the ball away in his own area and the ball makes its way to Silva who shoots low but compatriot De Gea holds on well. Tevez also has a go from the edge but it's also held by De Gea.
FOUR minutes added on.
United have a free kick 22 yards out, right of centre as Rafael is brought down. RVP territory...
GOAL! VAN PERSIE'S FREE KICK DEFLECTS IN!
Unbelievable! The Dutchman's free kick clips off Nasri's outstretched leg and beats Hart, dipping into the bottom corner. Remarkable.
There's now a delay as Ferdinand has a bloody face, he may have hit himself in all the jubilance or has he been struck by something from the crowd?
Rooney isn't penalised for a challenge on Balotelli and he then wins a free kick as Barry blocks his fellow Englishman's path.
City 2-3 United
Right at the end Tevez petulantly kicked Cleverley after the ball had gone out right under the nose of Fergie, who obviously wasn't best pleased.
City's 21-game unbeaten run in the league is brought to an end by Van Persie's free kick in the dying moments.
Three points for United means they are now six points clear of their rivals at the top of Premier League.
Goodness me. What a game of football! I honestly wasn't expecting such a goal and incident fest!
Rooney and Van Persie are speaking to Sky Sports News. Rooney says it's a massive boost to go six points clear while Van Persie, who was making his Manchester derby debut, says: "It's a really special way to end the game."
RVP: "Wayne asked me what I was going to do with the free kick...I told him I was going to shoot!"
Rooney: "To spoil [City's home record] is great."
Apparently some of the unsavoury scenes in the crowd after Van Persie's goal have continued after the final whistle. Tut tut.
If, for some reason, you've only just joined us, you can read our full match report, with plenty of images, by clicking here.
Thanks for joining Sports Mole this afternoon for a simply memorable Manchester derby. Be sure to stick around throughout the afternoon and evening for plenty of reaction to United's extraordinary triumph. If you're after more live action then you can follow Everton-Spurs here and West Ham vs. Liverpool (ko. 4pm) here. Until next time, goodbye!
