The Owls Under-21s lost out by a single goal away at Leeds on Monday afternoon.
Against a Leeds side that featured several first team players, an early second half strike from Eogham Stokes was the difference at Thorp Arch.
Wednesday were put under early pressure as Cameron Dawson saved well from Leeds midfielder Tommaso Bianchi.
Congolese international Jordan Botaka was then denied by Dawson, who made a smart save with his feet at the back stick.
The deadlock was broken moments after the resumption in the second half when Stoke fired home from inside the 18-yard box.
Warren Clarke went close to levelling for the Owls in the late stages when his strike from distance was saved by Leeds goalkeeper Bailey Peacock-Farrell.
Neil Thompson said: “It was a tough game against a very decent Leeds side.
“We had one or two chances in the first half, Jack Stobbs delivered some good crosses into dangerous positions and we came in 0-0 at half time.
“After that, we didn’t really get going and they edged the second half.
“It was a good test for the boys and you could tell the experience they had with those four or five first team players.
“But we still created chances and it’s another game where we have lost by the odd goal. We need to turn that around but it’s small margins at the moment.
“I thought Cameron Dawson did really well and he made three or four really good saves.”