Goals in each half condemned Hull City Under-23s to their first home defeat in the Professional Development League.
Strikes by Zak Brunt and Regan Slater secured Sheffield United all three points at the LNER Community Stadium.
Richard Naylor and Andy Dawson made four changes to the starting XI that defeated Crewe Alexandra 4-0 last time out. An unnamed trialist featured while Louis Beckett, Alfie Taylor and Henry Curtis all started.
The visitors started the brighter of the two teams as Angelo Capello volleyed wide, before a short corner routine saw Kyron Gordon hit the post with a well-struck effort.
Will Jarvis had the first clear-cut chance for the Tigers as he forced an acrobatic save from Jordan Amissah with a curling free-kick attempt. The Blades’ goalkeeper produced another good save to push away Tom Nixon’s cross, before the referee waved away penalty appeals after Jarvis thought he was fouled by Joe Starbuck.
At the other end, the visitors were awarded a penalty of their own after a foul on Frankie Maguire. Brunt stepped up and smashed his spot-kick past David Robson, despite the Tigers’ goalkeeper guessing the correct way.
It was end-to-end action in the opening exchanges of the second half as neat passing play between Jarvis and Curtis created space for Oliver Green to shoot, but his effort was blocked by Gordon, while Robson denied Nickseon Gomis’ effort at his front post moments later.
Substitute Sincere Hall came close to an equaliser, but his left-footed chance went over the bar, before McCauley Snelgrove saw his effort blocked by Kacper Lopata.
Sheffield United doubled their lead with six minutes left to play as Slater cut inside from the left wing before curling a right-footed effort into the far corner, as the Blades secured victory at the LNER Community Stadium.
Hull City: David Robson (GK), Tom Nixon ©, Henry Curtis, Harry Lovick, Trialist, Alfie Taylor, McCauley Snelgrove, Oliver Green, Josh Hinds, Louis Beckett (Sincere Hall 66’), Will Jarvis.
Subs Not Used: Tom Macauley (GK), Harry Wallis, James Carr, Billy Leach.
Sheffield United: Jordan Amissah (GK), Joe Starbuck, Nicksoen Gomis, Kyron Gordon, Kacper Lopata, Oliver Arblaster, Frankie Maguire © (Andre Brooks 76’), Zak Brunt, Antwoine Hackford (Hassan Ayari 67’), Regan Slater, Angelo Cappello.
Subs Not Used: Harvey Cullinan, Marcus Dewhurst (GK).