United's Under 18s recorded a hard-fought win in difficult conditions at the Hull City Academy, despite a late goal from the hosts making for a nervy final ten minutes.
The Blades had been largely in control of the match after goals from Leo Gaxha and captain Harrison Neal put Derek Geary's side 2-0 up at the break.
The first half an hour was a pretty even affair, with Sam Kelly tipping over an early header whilst Gaxha threatened to open the scoring when he curled an effort just wide.
Zak Brunt when even closer on the half hour mark as United started to take control of the match, the forward firing a powerful effort just wide from the edge of the box.
United did take the lead on 36 minutes. Good work from Brunt on the left opened up an opportunity for Clark Greaves, the striker's curling effort deflected into the path of Gaxha who hammered it home into the far corner at the first time of asking.
Almost as soon as it was one, it was two. Greaves beat his marker down the left, played a ball across the box which Brunt dummied, allowing skipper Neal to run in and bend a neat finish into the corner of the net.
United maintained their two-goal advantage after the break but Hull started to create chances of their own as the hosts looked for a way back into the match.
Centre-back Ben Adamson headed wide from a corner when he should have done better before full-back Jake Leake fired an instinctive effort wide after making his way into the box from his defensive position.
But still United continued to hold onto control of the result until the final ten minutes when Dan Hawkins turned and fired a low effort which Kelly couldn't stop creeping into the corner of the net.
Despite some late pressure from Hull, the Blades hung on for what was a deserved three points over the course of the match.
Blades: S. Kelly, J. Kelly, Anderson, Neal, Williams, Foulstone, Van Zandfleit, Maguire, Gaxha (Stainrod, Brunt (Ompreon 81), Greaves (Potts 63).
Unused: Amissah, Clarke.