Hello and welcome to Sports Mole's live text coverage of the Europa League semi-final second leg between Valencia and Arsenal at the Mestalla.

The Gunners head to Spain protecting a 3-1 lead from the first leg thanks to a couple of goals from Alexandre Lacazette and one from Pierre-Emerick Aubameyang.

Five of the previous 28 teams to lose the first leg of a UEFA Cup/Europa League semi-final by 2+ goals have ended up progressing, and Arsenal have never been knocked out of a European tie in which they won the first leg by two or more goals, progressing from all 27 previously.

VALENCIA TEAM NEWS!

STARTING XI: Neto; Piccini, Garay, Gabriel, Gaya; Wass, Parejo, Coquelin, Guedes; Moreno, Gameiro

SUBS: Domenech, Roncaglia, Diakhaby, Lato, Soler, Torres, Mina

ARSENAL TEAM NEWS!

STARTING XI: Cech; Sokratis, Koscielny, Monreal; Maitland-Niles, Torreira, Xhaka, Kolasinac; Ozil; Aubameyang, Lacazette

SUBS: Leno, Mustafi, Elneny, Mkhitaryan, Iwobi, Guendouzi, Nketiah

KICKOFF:  Arsenal show four changes from their 1-1 draw with Brighton last weekend, bringing in Cech, Maitland-Niles, Koscielny and Kolasinac - it is once again three at the back for the visitors. Valencia, who get the game underway, make two changes as Diakhaby and Mina are replaced by Garay and Gameiro.

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Emery left Ozil out for the quarter-final second leg against Napoli when protecting a two-goal lead, but the German playmaker is in the starting lineup tonight. It is an attacking XI named by the visitors, though they have mainly defended in the first few minutes.

Arsenal have looked very comfortable on the ball early on. Valencia are not really pressing their opponents and that is playing into the Gunners' hands. Remember, the home team require at least two goals tonight to progress through.

Gameiro holds his run and gets a cross in from the left. Koscielny does enough to get to the ball ahead of Gaya just inside the six-yard box. Valencia waste the corner and Guedes is unable to keep the ball in play from the next attacking move.

SHOT!  This is a good spell from Valencia, who have started on the front foot. Guedes works the angle and tries to curl the ball into the far corner, but he gets far too much height and whip on his shot and it ends in the stands.

SAVE!  Moreno gets a shot away from range that is easy for Cech, possibly playing his final game in professional football today, to deal with. Maitland-Niles charges forward from his wing-back position and tests Neto at the other end of the field.

GOAL!  VALENCIA 1-0 ARSENAL (KEVIN GAMEIRO)

Seconds after Maitland-Niles' shot, Gameiro is putting the ball in the back of the net at the other end of the field. No cover is offered down the flank by Torreira or Xhaka and Moreno makes the most of the space. The ball is played into the centre and Gameiro has a tap in at the back post.

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CHANCE!  Just like that, Arsenal are one goal away from exiting the Europa League - a 2-0 win would take Valencia through on away goals. The hosts miss a massive chance to score the second goal they are after as Maitland-Niles is again caught out down the home side's right. Moreno gets a shot on target from close range but teammate Gameiro blocks it.

SHOT!  That shot from Moreno may have been heading wide, but it is a major let-off for the Gunners. Valencia have started superbly and look as though they have another goal or two in the today. Arsenal need to get a hold of the ball and settle themselves, as Rodrigo blasts a shot inches wide from 20 yards.

GOAL!  VALENCIA 1-1 ARSENAL (PIERRE-EMERICK AUBAMEYANG)

As deadly as you like from Aubameyang! One attack for Arsenal and one goal, completely against the run of play. Lacazette flicks the ball into Aubameyang's path and his teammate sends his shot spinning away from Neto with the outside of his boot after first letting it bounce. Incredible finish!

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That away goal for Arsenal changes everything. They now lead 4-2 on aggregate, leaving Valencia requiring a couple of goals to take the game to extra time. The hosts started brilliantly and they have looked bright since the Aubameyang goal.

Every Valencia attack is coming down their left. Emery needs to resolve that, possibly by telling Ozil to drop a lot deeper or possibly by making an early change. This is a huge match for the Spaniard - he cannot afford to get his tactics wrong.

The ball drops for Wass to strike in the box but, under pressure from Monreal, he cannot keep the ball down. Valencia need to keep doing what they have been doing - the Arsenal goal was a sucker punch but they have been very positive in the final third.

Arsenal manage to get the ball into the opposition half and win themselves a corner. The set-piece is pretty decent but Aubameyang cannot keep his headed effort on target. Half an hour played and it is so far so good for the Gunners.

SHOT!  Valencia switch the ball and get some success. Parejo is picked out in a shooting position but he is unable to test Cech in the Arsenal goal. Los Che are giving Arsenal's defenders a lot more to think about tonight compared to a week ago.

UPDATE! Aubameyang has netted 27 goals in all competitions this season, a haul only Sergio Aguero (31) can better among Premier League players. Meanwhile, in the other semi-final taking place tonight, Loftus-Cheek has given Chelsea a 1-0 lead on the night and a 2-1 advantage on aggregate.

Former Arsenal midfielder Coquelin injures his back in an aerial challenge with Aubameyang and has to leave the field to receive some treatment. That two-minute stoppage has helped to break up the game, which favours Arsenal more so than their opponents.

SAVE!  Monreal's run pulls a couple of Valencia players away and Aubameyang, looking as sharp as ever tonight, is given time and space to get a shot away from 20 yards. It is a straightforward one for Neto to deal with down the middle, though.

CLOSE!  Valencia fans are getting frustrated as Arsenal have been on top over the last five minutes. Los Che manage to get the ball forward, though, and they win a free kick when Torreira takes out Guedes. Parejo stands over the ball and sends it just wide of the target, with Cech seemingly beaten.

YELLOW CARD!  Lacazette is also looking very sharp for the visitors. The striker gets to the ball just before Garay, who catches his opponent a little late. The referee reaches into his pocket for the first time today - the correct call, despite Garay's protestations.

OFF THE POST!  Lacazette and Aubameyang are bossing this game for Arsenal. The latter holds up the ball in the box after getting past Gabriel and squares it for his striker partner, who cannot quite wrap his boot around the ball. It clips the outside of the post on its way behind.

This first half has flown by. With two minutes of the half to play, Gaya is cautioned by the referee for diving in the box. Maitland-Niles did stick a leg out but the left-back - making a good overlapping run - tried to instigate the contact.

The opening 45 minutes are up but we are going to play a further couple of minutes. Arsenal boss Emery will be happy with how this first half has panned out, having seen his side start very slowly but recover to take complete control of the tie.

HALF TIME:  VALENCIA 1-1 ARSENAL (2-4 ON AGGREGATE)

The sides go into half time all square at 1-1 on the night, but Arsenal hold a 4-2 advantage on aggregate. Valencia require a couple of goals in the second half and, on the basis of the opening half an hour or so, you would not bet against them scoring those two goals. The Gunners may well need to score again to completely kill off the tie.

Marcelino made a couple of changes to Valencia's starting lineup and it was one of those players, Kevin Gameiro, who opened the scoring on the night 11 minutes in.

Valencia hit Arsenal on the counter after Ainsley Maitland-Niles got forward and tested Neto, with neither Lucas Torreira or Granit Xhaka providing cover for the wing-back.

Rodrigo Moreno made the most of the space down the left by carrying the ball forward and crossing for Gameiro to convert at the back post.

Los Che started the match in an attacking manner and nearly had a second, only for Gameiro to block Rodrigo's shot in front of goal.

Against the run of play, though, and from their first serious attack of the night, Alexandre Lacazette flicked the ball on for Pierre-Emerick Aubameyang to send it spinning past Neto with the outside of his boot.

Aubameyang tested Neto soon after and Goncalo Guedes sent a free kick marginally wide of the post, but it was Arsenal who came closest to scoring a second before half time as Lacazette skimmed the outside of the post from 10 yards after being teed up by Aubameyang.

BENCH WATCH!

VALENCIA SUBS: Domenech, Roncaglia, Diakhaby, Lato, Soler, Torres, Mina

ARSENAL SUBS: Leno, Mustafi, Elneny, Mkhitaryan, Iwobi, Guendouzi, Nketiah

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KICKOFF:  Arsenal get us back up and running at the Mestalla. The Gunners need to see out the next 45 minutes without conceding twice and they will be in the Europa League final, where London rivals Chelsea will likely await.

There is a nervy moment for Arsenal early in the second half as Piccini controls the ball in the box, spins and gets a shot away. It could have ended anywhere but Coquelin got in the way. The Gunners are going to have to do plenty of defending over the next 42 minutes.

It is end-to-end stuff now as Aubameyang picks up the ball and takes on the shot, which deflects behind for a corner. Aubameyang perhaps could have played in Kolasinac on the overlap instead. The corner comes to nothing.

GOAL!  VALENCIA 1-2 ARSENAL (ALEXANDRE LACAZETTE)

Lacazette scores for the third time in the tie to surely send his side into the final. The Frenchman drags the ball away from Piccini and curls it past Neto into the bottom corner of the net from 15 yards. Credit to Aubameyang, too, because he won the ball off Gaya while on the floor in the build-up.

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UPDATE! At the same time Lacazette was scoring to send Arsenal through to the final - surely! - Jovic was equalising for Frankfurt at Stamford Bridge. That one is heading to extra time as things stand. That is no longer a possibility here.

SHOT!  Guedes cuts in from the left and tries to catch out Cech at his near post. The shot from 19 yards ends in the side-netting.

VALENCIA SUB! Los Che, who require four goals to win this tie, bring on Soler for Piccini. The hosts are desperately trying to get their supporters back on their side but this match is over. A shot in the box hits Sokratis on the back - not the arm, as a couple of home players claimed.

GOAL!  VALENCIA 2-2 ARSENAL (KEVIN GAMEIRO)

Valencia needed four goals - now they need three thanks to Gameiro's second of the evening. The ball is slipped through for Parejo, who cuts is back for Moreno. The striker's shot hits Gameiro in front of goal and he is able to bundle it over the line.

We have learned nothing new about Arsenal today. They look very good whenever Aubameyang and Lacazette get on the ball, but the less said about their defence the better. Monreal has just been challenged and looks in need of treatment.

ARSENAL SUB! Mkhitaryan replaces Ozil, who takes an age to leave the field and is cautioned by the referee for time-wasting. Emery still does not look too relaxed on the bench - there have been too many comebacks this week for that!

SHOT!  Nobody closes down Garay and the centre-back lets leash from range. The ball flew inches wide of the target, much to the relief of Cech and Arsenal's travelling supporters, who are making plenty of noise this evening.

This is good defending from Sokratis to ensure that Valencia's latest attack comes to little. Wass gets a cross into the box as the hosts keep up the pressure, but Cech gets enough to the ball to stop Moreno from swooping in.

GOAL!  VALENCIA 2-3 ARSENAL (PIERRE-EMERICK AUBAMEYANG)

Aubameyang wins the ball back for his side and rounds off the move to send the Arsenal fans wild - they are cruising into the final. Maitland-Niles deserves credit for knocking the ball past his man down the right, before sending the ball into the six-yard box for Aubameyang to convert at the front post.

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SUBS! Torres and Mina come on for Guedes and Rodrigo as Marcelino makes his second and third changes of the game. Mustafi is on for Kolasinac in Arsenal's latest sub, with the outgoing player struggling from cramp.

Arsenal now lead 6-3 on aggregate for those who have lost track. It is safe to say that it is game over, even in this week of incredible comebacks. The Gunners are looking the more likely to score the game's next goal, too, with Valencia struggling for motivation.

UPDATE! Chelsea and Frankfurt are still locked at 2-2 on aggregate in West London, so it is looking as though they will be heading to extra time. Arsenal have been very clinical over these two legs and have booked their place in the final with plenty still in the tank.

Soler has a go from the angle but is unable to find the target with his shot. Valencia are trying to grab a foothold in the match but they are not going to score four times in the remaining 12 minutes. Emery appears to be readying another change.

Guendouzi is on for Torreira in the final change of the evening. Both sides would probably accept the full-time whistle now. Arsenal have a trip to Baku to look forward to in a few weeks' time.

Arsenal have plenty of players back behind the ball. There is no space in behind for Valencia so Gaya has a go from range and is a yard or so wide with his shot. Both teams are pretty much going through the motions now.

Mkhitaryan sends in a dangerous cross from the right which loops off Garay and behind for a corner. Aubameyang maybe could have done a little more to convert the ball before it went behind, but there was no need to risk injuring himself with his side well in front.

Arsenal are enjoying a spell on top now, seeing out the game with ease. Their travelling supporters are loving this stress-free evening. The referee is unlikely to add on more than a couple of minutes, knowing that both teams are happy to hear the whistle.

GOAL!  VALENCIA 2-4 ARSENAL (PIERRE EMERICK-AUBAMEYANG)

Brilliant from Aubameyang! The striker completes his hat-trick by absolutely thumping the ball past Neto into the roof of the net. He played a one-two with Mkhitaryan and then converted despite the angle being slightly against him. It is now 7-3 on aggregate!

Just two minutes have been added on at the end of the match, the first of which we have already played. Valencia have run into two strikers in deadly form - that has essentially been the difference between the sides.

FULL TIME:  VALENCIA 2-4 ARSENAL (3-7 ON AGGREGATE)

Something must have been said at the full-time whistle as both sets of players squared up. The bottom line, though, is that Arsenal are heading to their first European final in 13 years thanks to one of the most clinical displays you will see. Five shots on target, four goals, three of those from Aubameyang. Valencia were simply outclassed over the two legs.

That concludes Sports Mole's live text coverage of events from the Mestalla. An on-the-whistle report can be found by clicking here, and be sure to follow the remainder of extra time in the other semi-final between Chelsea and Frankfurt right here. Thanks for joining!