United U18s saw their seven-match unbeaten run in the Professional Development League ended at Shirecliffe on Saturday.
George Hirst, son of former Owls favourite David, netted a brace, which was enough to see all three points head back to S6.
United started best, with Mallon a constant threat to the visitors and from his excellent delivery, Hallam just failed to convert.
But the home side were punished for not making their early dominance count as Wednesday took the lead in the 33rd minute, HIRST intercepted a pass before racing clear and cooling slotting past the advancing Perryman.
Before the break, Gilmour saw a goal bound effort blocked, before United had strong appeals for a penalty waved away by the referee after Charlesworth appeared to be upended as he entered the box.
The second-half followed a similar pattern to the first, but again, despite enjoying plenty of the ball United struggled to find a spark to break down the visitors' backline.
Greaves and Parkhouse were introduced from the bench, although it was Hallam and Mallon who looked the most likely to fashion an equaliser.
But, the Owls put the game to bed in the 80th minute as HIRST got a decisive second, side footing home with his right foot.
Blades: Perryman, Chalesworth, Ford, Gilmour, Gilmour, Cummings, Graham, Stewart (Greaves 64), Slater, Burton (Parkhouse 73), Hallam, Mallon.
Unused: Hawkes, Warhurst, Cantrill.