Fernando Forestieri made a hero’s return as the Argentine striker came off the bench to fire the only goal of the game against Cardiff at Hillsborough.
Having sat out the last five games through injury, Forestieri proved the difference in breaking down the resilient Bluebirds, who looked to be taking a point back to the Welsh capital.
But with six minutes to go, the decisive moment of the game saw Forestieri head a dramatic winner to keep his side in the top six.
Wednesday started on the front foot and almost made their pressure count nine minutes in.
Ross Wallace picked up possession on the edge of the box and unleashed a low drive that Allan McGregor did exceptionally well to push on to the post.
Wednesday continued to dominate and penalty appeals waved away after Jack Hunt tangled with Kadeem Harris.
It was Cardiff, though, that fashioned the best chance of an ordinary opening 45 when Joe Rallls ghosted into the box but shot straight at Keiren Westwood and the hosts cleared the danger.
Then, just before the break, came the big talking point of the first half.
Daniel Pudil was felled by Junior Hoilett, who was relieved to see the referee issue a yellow card instead of what could have been red.
Jordan Rhodes and Forestieri were introduced from the bench as the Owls struggled to break down a resilient Cardiff side.
Tom Lees headed wide from a Wallace corner, Reach saw a shot charged down before Wednesday finally got their goal with six minutes to go.
Rhodes fired a snapshot that McGregor parried but only into the path of Forestieri, who stooped to head into the roof of the Kop net.
The goal was nothing more than the Owls deserved and so too the lion's share of supporters inside Hillsborough, who were right behind their team from the start and ventured home happy at the end.
Wednesday: Westwood, Hunt, Sasso, Lees, Pudil, Wallace, Bannan, Jones (Forestieri 62), Reach, Fletcher (Nuhiu 74), Hooper (Rhodes 64)