United's Under 23s started the year with a 4-2 loss at Crewe as triallist Cheikh Ndiaye and striker Simeon Oure's goals weren't enough to take anything from the encounter.
It was a frantic end-to-end game which saw both sides create plenty of chances throughout, but Crewe were the more clinical side, largely due to a hat-trick from striker Lewis Reilly.
United could have been ahead in the opening minutes as Harry Sheppeard sent an effort wide before Oure fired an effort straight at David Richards in goal.
The Blades were made to pay a minute later when Reilly scored the first of his three goals with a header from point blank range.
United were forced into a change after 20 minutes but Harry Boyes had the immediate desired impact when his cross found Ndiaye who headed home from close range.
Boyes nearly scored straight after as he volleyed wide Oure's cross and Blades were once again made to pay as Crewe went up the other end and Reilly got his second, once again from close range.
United looked to respond early in the second half as Jake Young brought a brilliant save out of Richards and for the third time the hosts made United pay as Reilly claimed his hat-trick after the defence failed to clear a Crewe corner.
Keenan Ferguson and George Broadbent were sent on and the latter played a big part in United pulling it back to 3-2 when he charged down a clearance and Oure fired home unmarked inside the penalty box.
But two minutes later it was 4-2 and there was no coming back on this occasion. Reilly was played through but Jordan Amissah denied him his fourth, only for Owen Dale to hammer home the rebound.
George Cantrill had a good chance to once again reduce the deficit from a corner but it was Crewe who took the points.
Blades: Amissah, Cantrill, Gomis, Ndiaye (Broadbent 70), Graham, York, Sheppeard, Oure, Young, Greaves (Ferguson 62), Mallon (Boyes 21).
Unused subs: Dewhurst, Neal.