United kicked off the pre-season action with a heavy defeat at Burton Albion on Saturday.
Playing for the Bass Charity Vase, Nigel Clough, formerly of Burton, gave 22 members of his squad 45 minutes each at the Pirelli Stadium.
However, Burton raced into a 3-0 half-time lead and added a fourth late on.
Burton: Anyon, Edwards, Taft, Sharps (c), McFadzean, MacDonald, Weir, Palmer, Akins, Beavon, Knowles. Subs: Lyness, Cansdell-Sherriff, McGurk, Slade, Harness, Ribiero, Verheydt, Shelton, O'Brien, Austin, Cranston, Cutajar.
United's 1st half team: Howard, Davies, Collins, Butler, Paling, Doyle, Reed, Dimaio, Campbell-Ryce, Murphy, Porter.
Academy youngster Paling began for United at left-back, but the home side's left-back, McFadzean, on loan from the Blades, almost presented Porter with the first chance but goalkeeper Anyon tidied up.
Burton then opened the scoring with their first real chance, just over five minutes had elapsed. From an Akins cross, Palmer failed to get a shot away but MacDONALD was unmarked on the left to side-foot into the roof of the net.
Campbell-Ryce delivered a couple of inviting crosses from the right but the Blades went two behind on 13 minutes. Beavon broke down the left and delivered a low cross for AKINS, who pulled away from Paling, to despatch into the top corner.
It almost got worse for the Blades on 23 minutes. Beavon got the better of Howard on the edge of the box and with the goalkeeper out of position, Butler prevented Knowles from getting a shot away.
Dimaio fired wide for the Blades after good build up on the edge of the box and Doyle could not keep his shot down after Dimaio, Reed and Porter caused problems in the home defence.
Penalty shouts at both ends were ignored by referee Moss but Burton extended their lead to three just before the break. This time a straight forward corner from McFadzean was headed home by the unmarked KNOWLES.
United's 2nd half team: Long, Alcock, Maguire, McGahey, Harris, Crawford, Basham, McGinn, Scougall, Baxter, De Girolamo.
The Blades began the second half - including triallist Crawford on the right - on the front foot, De Girolamo turned his marker but couldn't get a shot away and then a Baxter effort was deflected just wide.
New boys Basham and McGahey received warnings from the referee following tackles, no doubt keen to impress, whilst the man in the middle waved away De Girolamo's appeal for a penalty on 70 minutes.
There was a marked improvement from United's second half team. From Alcock's crossfield ball, Harris headed down but Scougall was denied by Lyness. On 78 minutes another deep cross from Alcock saw Maguire win a header at the back post that looked goalbound but Cansdell-Sherriff kicked away.
Burton, however, extended the lead in the closing stages. An impressive run from Harness resulting in CUTAJAR half-volleying home, despite Long getting a hand to the ball.
Baxter and De Girolamo were off target with late efforts and the attendance of 2,124, more than a 1,000 of which were Blades, was announced whilst the later stages included thunder, lightning and rain before the final whistle confirmed the Bass Charity Vase was standing with Burton Albion.