United's U18s slipped to a defeat against Nottingham Forest, in their first game since the Christmas break.
United started the game well and battled hard throughout in tough conditions but failed to create any clear cut chances in the first-half.
Things were made harder for the Blades when defender Weaver was forced off due to injury, forcing a change of system.
The second half saw the hosts apply more pressure but Dewhurst was on hand on a number of occasions to maintain parity with a string of fine saves.
But he was powerless to prevent Forest opening the scoring in the closing stages as a cross was turned home with just five minutes to go.
And Forest put the game to bed with a second as United committed bodies forward in search of an equaliser, only to be caught on the break.
Blades: Dewhurst, Williams, Boyes, Weaver (Capello 23, Foulstone 75), Gordon, Cutts, Hawkes, Belehouan, Potts, Parkhouse, Ackroyd (Neal 80).
Unused: Warhurst, Kelly.