United's U18s saw their two game winning streak come to an abrupt end, with a 4-0 defeat against a well-drilled West Brom side at Shirecliffe.
The Blades were made to pay for missed opportunities, especially in the first twenty minutes, before succumbing to Albion's dominant display.
The hosts started the game well and Pennycooke-Morgan could have put them in front as early as the first minute, but his shot was off target. Pomares then supplied two pinpoint crosses from the left but nobody was able to get on the end of them.
As United continued to apply the pressure James came close on two separate occasions, only to see his shot and then a header comfortably saved.
The first-half looked like finishing goalless, until Albion were awarded a soft penalty. That seemed to kick them into action and from then on United were up against it.
Five minutes into the second-half it was two, when the young Baggies seized possession in midfield, before finishing well. Murray responded by rattling the post from a free-kick and Slew looked a real handful up top.
Albion were in no mood to rest on their laurels and demonstrated their ability by adding two more goals late on which totally deflated United's youngsters.
Coach Kevin Fogg was understandably upset with the scoreline and elements of the game, but drew a crumb of comfort from West Brom's assessment of proceedings:
"Keith Downing, their coach, said it was a game of two halves, but I am really frustrated because we have failed to build on our recent performances that saw us get consecutive victories.
"WBA were outstanding and a very strong and skilful outfit, but it is disappointing that the five lads on the bench couldn't pit their wits against one of the best teams we have faced this season, because of the Reserve game on Wednesday."
Blades: Billard, O'Kane, Pomares, Williams (Wilkinson 75), Kennedy, Darlow, Lammy, Murray, Gregory (Slew 70), James, Pennycooke-Morgan (Ahmadi 75).
Unused: Foster, Maguire.