The Owls posted their first away league win, beating Brentford 2-1 in a dramatic encounter at Brentford.
Atdhe Nuhiu’s penalty eight minutes before half time opened the scoring but the Bees hit back after the break through Alan Judge.
Then, just as the game was heading for a draw, substitute Lucas Joao planted a late, late winner to seal all three points.
Both sides, though, were reduced to ten men, with James Tarkowski seeing red for Brentford and substitute Jeremy Helan following suit for the Owls.
It was back to Championship duty for Wednesday following their Capital One Cup heroics at Newcastle in midweek and they took the confidence in the camp into the early stages at Griffin Park.
Dangerous duo Ross Wallace and Nuhiu linked up well, with the latter executing a diving header that flew straight down the throat of David Button.
Wallace then sent in a long ranger that forced Button into an unorthodox punched save before Nuhiu headed narrowly wide.
Livewire Barry Bannan served a delicious centre that just evaded Marco Matias at the back post midway through the first half as Wednesday sought the advantage.
And they almost got exactly that on 24 minutes when a pinpoint corner from Wallace was met with power by Nuhiu but the striker’s header thumped against the crossbar and out.
The Bees had a rare attack that ended with Jake Bidwell brushing the crossbar following a terrific Alan Judge feed – but then the home side were hit by a double blow.
On 36 minutes, a sublime ball from Bannan landed at the feet of Nuhiu ten yards from goal, who was about to pull the trigger before being upended by Tarkowski.
The referee pointed to the spot and after consulting with his assistant duly dismissed the defender and Nuhiu scored from 12 yards.
Brentford needed the half time whistle and regrouped to ask more questions in the second period.
Judge hit a curling free kick into the danger zone just before the hour that evaded a packed penalty area and smacked against the post.
But the Owls fought fire with fire and introduced Joao from the bench to supplement the attack.
The move had the desired effect as Brentford’s impetus was stifled, with Wednesday enjoying more of the play.
But the Bees still probed and Keiren Westwood was alert to deny Bidwell after the full back charged forward on the overlap.
The hosts continued to press and were rewarded 14 minutes from time.
Judge neatly controlled a deep diagonal ball and struck a sweet shot right into the far corner to haul Brentford level.
Moments later, Wednesday were reduced to ten men when Helan picked up his second yellow card and it was backs to the wall for the closing stages.
Lasse Vibe blasted over the bar with the goal at his mercy but still there was time for drama at the other end in the last minute as Joao capitalised on a defensive slip to burst forward and slide past Button to take the plaudits.
Wednesday: Westwood, Turner, Hutchinson, Matias (Joao 63), Nuhiu (Lopez 81), Lees, Lee, Hunt, Wallace, Pudil (Helan 41 s/o 79), Bannan