A late Leroy Lita header handed Wednesday a crucial win over promotion-chasing Crystal Palace on Saturday.
And the Owls were good overall value for the points, giving an excellent account of themselves against the in-form Eagles.
Chances were few for both sides but Lita converted the one that mattered as Wednesday extended their recent purple patch.
Unbeaten in six games and having suffered just one defeat in 11, the Owls were out to move clear of the Championship trapdoor and started in confident mood.
Lewis Buxton sent a curling free kick narrowly over the crossbar before David Prutton’s fierce snapshot from distance followed suit.
Lita then found space in the box but just failed to control an accurate feed from Buxton as Wednesday bossed the early exchanges.
Palace, missing injured talisman Wilfried Zaha, were on the back foot as the first half unfolded and only rarely ventured upfield.
When they did, the visitors met with a solid and well-drilled rearguard, boosted by the return of captain and former Eagles defender Anthony Gardner.
The contest kept a similar theme leading to the interval, with the Owls in the box seat, and they might have headed up the tunnel a goal to the good had Damien Delaney not blocked a fizzing close range drive from Kieran Lee with keeper Julian Speroni beaten.
The Londoners needed to up the ante after the break and did exactly that from the restart when Yannick Bolasie burst down the right and Giles Coke almost headed the resultant cross into his own net.
Loanee Scott Dobbie forced Chris Kirkland into a low near post save five minutes later, then Kagisho Dikgacoi tried his luck from 25 yards and was unfortunate to see the ball whistle wide.
Dave Jones introduced Gary Madine with Connor Wickham making way as Wednesday sought to recapture their earlier dominance and Jeremy Helan, on for Lee, also entered the fray.
The changes swung the game back in the Owls’ favour, although Palace had armoury of their own from the bench, most notably Kevin Phillips.
But it was Bolasie who went close on the counter with 20 minutes to go when the tricky winger bore down on goal and Kirkland had to be alert to thwart the danger.
The game’s decisive moment, though, came on 81 minutes when Wednesday stole into the lead.
Michail Antonio stood up a teasing cross right into the danger zone and Lita climbed the highest to bury a powerful into the back of the net and secure a priceless three points.
Owls: Kirkland, Buxton, Gardner, Llera, Pugh, Lee (Helan 63), Coke, Prutton, Antonio (J Johnson 82), Lita, Wickham (Madine 57)
Unused substitutes: Davies, Taylor, Semedo, McCabe
Crystal Palace: Speroni, Richards, Parr (Butterfield 88), Bolasie, Dikgacol, Dobbie (Wilbraham 88), Jedinak, Murray, Williams (Phillips 68), Delaney, Ramage
Unused substitutes: Price, Marrow, Easter, Moxey