United's U18s saw their five-game unbeaten run come to an end in West Yorkshire on Saturday.
With Leeds controlling the ball in the early stages, United were forced to play on the counter leading to bright runs from both Potts and Capello but both Parkhouse and Doherty failed to convert the half chances that came their way.
The first goal came in the 20th minute as a cross from the right was met sweetly and flew past Warhurst low to his right-hand side.
And 14 minutes later the hosts doubled their advantage as a though ball found the onrushing striker who slotted home into the bottom corner.
As the break approached the Blades almost reduced the deficit but Ompreon's header went just over the bar from six yards.
Leeds put the game beyond the Blades in the 65th minute, despite a spell of United pressure, as a strike from 20 yards beat Warhurst to condemn Derek Geary's side to a first loss in six.
Blades: Warhurst, Weaver, Capello (Kelly 59), Belehouan, Gordon, Cutts, Broadbent, Doherty (Hawkes 45), Parkhouse, Ompreon (McClellen 45), Potts.