United's U18s saw their winning start to the new campaign ended by Crewe.
Despite a brace from the in-form Jordan Hallam, the Blades paid the price for poor defending against the Alex.
United started brightly, but Parkhouse was guilty of wasting two early openings. And those misses would prove costly in the 18th minute as the home side opened the scoring following a scramble in the penalty area.
Crewe doubled their advantage six minutes later as a long ball forward saw the home striker get in behind Brown before lashing home.
On the stroke of half-time, the Blades gave themselves a lifeline though with HALLAM stabbing home after mix-up in the Crewe defence.
Just when the Blades appeared to be getting a foothold in the game, Crewe scored a goal either side of the hour make to effectively put the game beyond the visitors.
Firstly, appeals for a foul on Semple were ignored prior to a tap in from a cross from the right, then nine minutes later the hosts benefited from poor marking to score the fourth with a free header.
The Blades battled gamely though and scored two late consolation goals, with HALLAM netting his second and United's third in the 89th minute, but despite a late charge the Railwaymen held on for a deserved victory.
Blades: Perryman, Charlesworth, Brown (T. Smith 64), Gilmour, Graham, Semple, Cummings, Slater, Burton, Parkhouse, Hallam.
Unused: Hawkes, Warhurst, Ford, Portman