Wednesday turned in a disciplined, impressive all-round performance to beat league leaders Leeds 2-0 at Elland Road.
Late goals from Jacob Murphy and substitute Atdhe Nuhiu sealed a super win that was thoroughly deserved.
If the first half belonged to Leeds, Wednesday were superior for much of the second and the two-goal burst at the last capped a memorable White Rose derby.
As expected, the hosts came out of the traps with intent and bossed the ball through the early exchanges.
The Owls were largely on the back foot but did show flashes of threat on the counter, as evidenced 15 minutes in when Adam Reach broke and looked for Murphy but Liam Cooper got the merest of touches to divert the danger.
And moments later Leeds came within a whisker of taking the lead. Calvin Phillips sent an accurate free kick right into the danger zone where Jack Harrison poked wide with all of the goal to aim for.
Patrick Bamford did have the ball in the net midway through the first half but a raised flag cut short the celebrations.
The impressive Harrison forced Cameron Dawson into a low diving save as Leeds mounted the pressure and Helder Costa might have done better moments before the half time whistle but fired high over the crossbar.
Bamford did the same just after the resumption following good work from Costa before the Owls hit back with Winnall inches away from Murphy’s cross at the back post.
Winnall shot over after a bout of Wednesday possession and as the second half progressed, the visitors grew more and more into the game.
With a resolute backline the foundation, the Owls kept Leeds at bay whilst launching breaks from which they looked dangerous.
And with the contest seemingly heading for a stalemate, Wednesday struck not once but twice at the last.
First, Murphy was sent through on goal down the right side of the area by Nuhiu and unleashed a fierce drive that nestled in the bottom corner.
Then, deep into stoppage time, Reach pulled back for the advancing Nuhiu, who thundered high and beyond Kiko Casilla to put the game to bed.
Wednesday: Dawson, Urhoghide (Hutchinson 84), Iorfa, Börner, Fox, Murphy, Bannan, Lee, Luongo (Pelupessy 77), Reach, Winnall (Nuhiu 68)
