United's U23s were on fire on the hottest day of the year so far as they put Crewe to the sword on Thursday.
First-half goals from skipper Regan Slater and Tyler Smith helped extend the young Blades unbeaten run to six matches.
United came out firing on all cylinders and went ahead after eight minutes as Smith burst down the right and crossed to Gilmour who in turn teed up SLATER to finish.
Shortly after, Smith had the chance to extend the lead but his left footed shot flew just wide of the post.
Ten minutes before the interval United doubled the advantage though as Cantrill picked up the ball on the left and sent through SMITH who finished to put the visitors in complete control.
The game edged further away from the hosts early in the second period, as Walker was dismissed for an off the ball incident.
Crewe looked for a way back into the game but couldn't break through United's stern defence, although Ferguson had to head off the line with Dewhurst out of position.
But the United stopper atoned for that in the latter stages of the contest, excellently denying Lundstram, who found himself in on goal.
Blades: Dewhurst, Portman, Cantrill, Doherty, Ferguson (Broadbent 85), Semple, Gilmour, Slater, Smith, Oure (Potts 60), Crankshaw.
Unused: Greaves, Weaver.