The visitors' defence was almost caught out within moments of the start when Jacques Maghoma received the ball in space, but with only the keeper to beat, the Wednesday forward lost his footing.

However, the hosts made no mistake on 20 minutes when yet more questionable organisation in the Leeds backline afforded Reda Johnson time to slot the ball past Paddy Kenny.

Reda Johnson of Sheffield Wednesday celebrates his goal with Atdhe Nuhiu during the Sky Bet Championship match between Sheffield Wednesday and Leeds United at Hillsborough Stadium on January 11, 2014 © Getty Images

Chris Maguire came close to increasing the Owls' advantage when his low drive from outside the area was parried away by a besieged Kenny.

Wednesday, who had only recorded four league wins this season before this game, found a second on the stroke of half time when the visitors' defence backed off to allow Kieran Lee time to pick out Atdhe Nuhiu, who scored from close range.

Leeds manager Brian McDermott introduced Matt Smith in attack to try to inspire a fightback, but those plans were quickly cast aside when Smith was given a straight red by referee Lee Probert for what was deemed a dangerous challenge on Johnson with barely 60 seconds gone after half time.

Chris Kirkland of Sheffield Wednesday breaks up a fight, after Matt Smith of Leeds United challenge on Reda Johnson of Sheffield Wednesday during the Sky Bet Championship match between Sheffield Wednesday and Leeds United at Hillsborough Stadium on Januar © Getty Images

The hosts quickly added insult to injury when Connor Wickham's near-post effort was poorly dealt with by Kenny and trickled into the Leeds net.

Wednesday added a fourth, albeit with a bit of luck when Maguire's free kick took a wicked deflection off the wall and wrong-footed the helpless United keeper.

More poor defending led the Owls' fifth when Marius Zaliukas rushed out to win the ball on the halfway line but missed it completely, allowing substitute Caolan Lavery to race in on goal and, with the help of the post, find the bottom corner of the net.

Brian McDermott. manager of Leeds United looks on during the Sky Bet Championship match between Sheffield Wednesday and Leeds United at Hillsborough Stadium on January 11, 2014 © Getty Images

In stoppage time, Brian McDermott's misery was complete when the hosts found a sixth with Lavery beating Kenny with almost the last kick of the game.

The emphatic result puts daylight between Wednesday and the Championship relegation zone, while Leeds remain outside the playoff places, with other sides yet to play on Saturday.