United returned to winning ways in the Professional Development League, edging an even contest against Nottingham Forest at Shirecliffe.
The prolific Jordan Hallam scored a second-half brace, with the winner coming three minutes from time, to ensure the Blades enhance their position at the top of the table.
The home side were on the front foot immediately against their Championship opponents, with Hallam having a couple of half chances inside the opening five minutes.
But three times before the break, United were grateful to goalkeeper Warhurst, firstly he save low to his right, then he pushed away a free-kick diving full stretch to his left, but he saved the best to last, making an excellent double save on the stroke of half-time.
And those saves were rewarded in the 56th minute as HALLAM fired home the rebound after Slater had been denied from the edge of the penalty area.
Burton wasted a good opportunity to make it 2-0 ten minutes later and in their next attack Forest punished that miss by equalising.
But the home side didn't panic, gradually they got back on top and with time running United's composure saw them snatch what proved to be the winner, HALLAM beat three defenders on the edge before firing home at the near post.
Blades: Warhurst, Charlesworth, Cantrill, Ford, Semple, Parkhosue, Greaves, Slater, Burton, Hallam, Hawkes.