The Owls suffered a late double blow at Norwich as Tony Pulis was denied his maiden win.
Josh Windass gave the visitors a second half lead but just as the finish line was in sight, goals from substitute Josh Martin and defender Max Aarons turned an enthralling game on its head.
It was hard on Wednesday, who were stout and well organised at the back, but the mounting pressure from the hosts finally told.
The Canaries, out to arrest a mini slump in form, were straight on the front foot and struck the woodwork inside three minutes.
Emi Buendia warmed the hands of Joe Wildsmith from a tight angle and Teemu Pukki picked up the scraps to hit the foot of the post.
The Owls were undaunted, though, and went just as close to opening the scoring. Barry Bannan delivered a wicked corner that Julian Börner nodded goalwards only to see the busy Buendia head off the line.
Kadeem Harris was thwarted by keeper Michael McGovern moments later before the contest settled into an even affair up to half time.
Grant Hanley saw a set piece drift wide for the hosts and Joost van Aken was inches off target from distance as Wednesday had the final say of a relatively equal first 45.
Hanley gave the Owls another fright five minutes after the restart, glancing narrowly wide, and Moses Odubajo went close at the other end.
But right on the hour, Wednesday broke the deadlock. Bannan fed Adam Reach down the left, the cross was a peach, and Windass planted his header past the diving McGovern.
It was rearguard action from there on in, with the Owls reliant on the counter as Norwich dominated the ball.
But home hearts were in their mouths on 70 minutes when Hanley tangled with Harris in the box but the penalty claims were waved away.
Joey Pelupessy forced McGovern into action before Wednesday were hit with two goals in three minutes.
First, on 81 minutes, Mario Vrancic threaded a neat ball down the left of the penalty area for Martin to slot beneath the advancing Wildsmith.
There was barely time for the Owls to recover before Norwich scored what proved the winner.
Aarons played a give and go with Pukki to motor into the danger zone and thump emphatically across Wildsmith and in.
Wednesday: Wildsmith, Odubajo (Kachunga 87), Lees, Börner, van Aken, Paterson, Iorfa (Pelupessy 53), Harris (Brown 87), Bannan, Reach, Windass (Palmer 65)