United's youngsters slipped to defeat at Hull City, despite taking the lead through George Broadbent.
The Blades started brightly with Lawrence going close with a good effort just five minutes in.
Soon after United would be ahead as BROADBENT curled a free kick into the top left-hand corner leaving the goalkeeper with no chance.
Hull would restore parity just before the break as an advancing runner was played through one-on-one and calmly finished past Dewhurst to level the scores.
After the interval United came close on a number of occasions with Ackroyd striking just wide and substitute Kelly drawing a good save from the Hull goalkeeper.
It was Hull who went ahead however with 15 minutes left to play as the ball broke free in the area and was struck home with purpose.
The hosts would seal the victory on the counter attack, as United threw bodies forward in search of an equaliser.
Blades: Dewhurst, Portman, Foulstone, Gordon, Williams, Oure (Neal 75), Broadbent, Hawkes, Ackroyd (C. Greaves 65), Ompreon (J. Kelly 72), Lawrence.
Unused: S. Kelly.