United wasted a host of chances in an open first half and were then clinically put to the sword by a quick Gary Hooper double amidst poor defending and goalkeeping within five minutes of the restart.
United were then denied a possible route back into the game when Liam Cooper bundled home Alex Mowatt’s free-kick for a ‘goal’ which was awarded by referee Anthony Taylor but then ruled out as Wednesday were attempting to make a substitution at the same time.
The loss condemned 15th-placed United to back to back league losses and made it five league games without victory with the Whites in desperate need of fresh blood in the January transfer window.
Steve Evans made two changes two his starting line up with one of them forced through the proposed sale of right back Sam Byram to Everton.
The head coach had still hoped to play the 22-year-old but Byram did not feature in the match-day squad with Alex Mowatt also dropping to the bench.
In came winger Stuart Dallas and Luke Murphy as part of a five-man midfield that also featured Liam Bridcutt, Lewis Cook and Mustapha Caryol as the other wide man.
Souleymane Doukara was selected as a lone striker with Mirco Antenucci on the bench along with former Motherwell striker Lee Erwin.
The Owls line up featured two changes with third choice ‘keeper Lewis Price starting in goal due to injuries to Keiren Westwood and Joe Wildsmith who played in mid-week but now has a back injury.
Wednesday also fielded their ‘reserve’ centre-back pairing of captain Glenn Loovens and Vincent Sasso due to injuries to former Whites defender Tom Lees and also the on loan Michael Turner.
Sam Hutchinson also came into midfield at the expense of Atdhe Nuhiu but the Owls team featured plenty of attacking flair with Gary Hooper playing his last game before heading back to Norwich and partnering former Leeds target Fernando Forestieri upfront.
And it was Forestieri who first threatened as a quick free-kick released the striker only to be flagged offside before thumping the crossbar.
Yet Leeds immediately threatened themselves when Carayol found space out wide on the left flank before unleashing an inviting low cross that evaded both Doukara and the Owls defence.
But the game’s first real chance arrived for the home side after five minutes when a fine right flank Jack Hunt cross was met by the onrushing Hooper whose header was put narrowly over the crossbar.
Moments later, Cooper was then required to produce some decent last-ditch defending to keep out Forestieri after Murphy’s miss-placed pass fell to Barry Bannan who produced a lung-busting run before releasing the front man.
Then, immediately at the other end, Leeds worked decent openings for first Cook and then Carayol but neither was able to take advantage.
And the Whites were then presented with an even better opportunity when Dallas raced away down the right flank before producing a decent low effort that Price palmed away but this time neither Cook or Doukara were able to convert the rebound.
As part of an end to end start, Forestieri then had more space then he realised when found in the area but placed a wayward pass rather than have an attempt on goal as looked likely.
Another five minutes passed before a Liam Bridcutt free-kick was easily dealt with by Price, after which Wednesday’s first corner was wasted by Ross Wallace.
Dallas then fired an effort well wide and after Bridcutt’s fine turn was followed by a wayward pass, another dangerous Dallas cross fizzed unconnected across the Owls goal.
Wednesday’s Hutchinson then became the first player to enter the notebook after scything down Carayol but United made a mess of the free-kick.
And Leeds were then presented with another fine opportunity when Cook was released down the right flank but after a determined run the midfielder fired his low effort wide of the left hand post.
Referee Anthony Taylor was then reaching for his yellow card again as Giuseppe Bellusci took out Forestieri and while the subsequent free-kick came to nothing the Owls were soon back on the attack with Forestieri’s low effort well saved by Silvestri.
But Leeds were certainly giving at least as good as they got and Doukara was the next to test Price with a low shot that was saved which proved the final effort of a goalless but entertaining half.
Leeds will have entered the break fancying their chances but matters very quickly changed just two minutes after the break when the hosts took the lead.
Wednesday were straight on the attack after Leeds lost possession from kick-off and Forestieri’s long range low effort was parried away by Silvestri for a corner.
A short corner was worked to Hutchinson whose cross then produced a mad scramble with Forestieri forcing the ball goalwards before Hooper eventually bundled the ball over the line.
And United’s afternoon very quickly went from bad to worse just three minutes later when Hooper bagged his and Wednesday’s second.
Forestieri eased his way through United’s midfield and produced a decent but not devastating low shot that Silvestri could only fumble to the onrushing Hooper who made no mistake in slotting home.
Leeds then almost completely pressed the self destruct button when Cook went in fiercely on Hunt but the midfielder was shown a yellow card when a red one would have been no surprise.
Wednesday were already in cruise control and in a rare Leeds foray Doukara was not in the right place to meet a decent cross from Dallas who continued to offer United’s biggest threat.
Forestieri then had another pop from 20 yards but this time Silvestri showed safe hands to gather before Forestieri then smashed another effort from range narrowly wide and over.
And Leeds then wasted a potential route back into the game when Murphy fed Doukara who unleashed a decent low effort but one that ultimately smacked the advertising boards behind the goal after striking the outside of the post.
Evans then made his first change in bringing on Mowatt for Carayol with 20 minutes left with Mowatt taking Carayol’s place on the left wing.
Wednesday’s Daniel Pudil was then booked for a trip on Giuseppe Bellusci, after which Evans hauled on Antenucci for Murphy with 15 minutes left as United changed their formation to a 4-4-2.
And the game then turned on a bizarre moment with 10 minutes left when United thought they had pulled a goal back through skipper Cooper.
Wednesday signalled for their first change with Forestieri withdrawn for Lucas Joao and United attempted to take a quick free-kick as the Italian headed off the field.
Leeds looked to have capitalised on the set piece as Cooper scrambled home Mowatt’s delivery but Forestieri was still heading off the field of play leaving the home side up in arms at the ‘goal’ which had been awarded by the official
The Owls players surrounded referee Taylor who then changed his mind and ruled the goal out, much to United’s dismay.
The Whites then almost scored from the free-kick retake but another scramble ended with a Scott Wootton effort going just over the bar.
Wednesday survived the drama and as the game entered its final stages, Wednesday made their final two changes with Jeremy Helan on for Wallace before Jose Semedo replaced two-goal Hooper.
But the game was by now done and dusted with Antenucci curling a late Leeds effort wide before four uneventful minutes of injury time passed before referee Taylor’s full time whistle.
Sheffield Wednesday: Price, Hunt, Sasso, Loovens, Pudil, Wallace (Helan 82), Lee, Hutchinson, Bannan, Forestieri (Joao 77), Hooper (Semedo 86). Subs not used: Dawson, Palmer, Sougou, Nuhiu.
Leeds United: Silvestri, Wootton, Bellusci, Cooper, Taylor, Dallas, Bridcutt, Murphy (Antenucci 74), Cook, Carayol (Mowatt 70), Doukara. Subs not used: Peacock-Farrell, Coyle, Bamba, Adeyemi, Erwin.