Following a creditable display in the FA Youth Cup against Everton last week, United's U18s slipped to a narrow 2-1 league defeat at Birmingham City over the weekend.
The visitors started the game with Coustrain, Khan and Cockerline linking up well on several occasions in the opening exchanges.
Heh wasted a great opportunity to fire the Blades in front in the 28th minute and United were punished three minutes later.
Partodikaromo was caught in possession deep inside his own half and slide rule ball saw the Blues get in behind Evans and Calvert-Lewin, leaving the onrushing striker the easy task of rounding Owen and tucking the ball home.
United's response should have been immediate, but the referee failed to play an advantage when Khan broke clear, opting to award a free-kick to the visitors in the middle of the park.
The Blades misfortune continued in the second period. Tom Charlesworth, a U15s right-back, making his U18s debut had performed well for the first hour, but after he failed to cut out a cross from the left, skipper Evans and Owen was powerless to stop the Blues doubling their lead from close-range.
This sparked a strong finish from the Blades. Cockerline failed to make the goalkeeper work from the angle, before Ishmail rattled the crossbar. COUSTRAIN made United's pressure pay off shortly afterwards, excellently drilling home from 14 yards.
This set up an end-to-end final ten minutes, but despite their best efforts, United couldn't find an equaliser.
United's youngsters are back in action at Nottingham Forest today (Tuesday), kick-off 1pm.
Blades: Owen, Charlesworth (Wright 62), Ptak (Kedman 45), Ishmail, Evans, Calvert-Lewin, Heh (Slew 69), Partodikaromo, Cockerline, Khan, Coustrain.
Unused: Eastwood, Fixter.