Albion’s already-qualified youngsters fell to defeat on the road in their final Premier League Cup Group C game against Hull City.
The Baggies, who had already secured their spot as group winners, were undone by two first-half goals by Stephen Kingsley and Billy Chadwick.
An impressive Kingsley strike handed the hosts the advantage, but Cheikh Diaby twice came close to an equaliser, firstly with a poked effort which was deflected wide and then with a close-range strike which he blazed over after a Yusuff Ojebode’s cross.
But Chadwick netted from inside the box into the bottom corner to add to Hull’s advantage.
Ethan Ingram hit a strike from range which went well wide, while Finley Thorndike was denied by great reactions from Harvey Cartwright in the Tigers’ net.
Then Thorndike skipped past two challenges inside the box but could only find the side-netting, as the hosts held on for victory.
ALBION: Cann; Ingram, Sharpe (Martinez 61), Shotton, Ashworth; Brown, Chambers (White 68); Ojebode, Thorndike (Taylor 77), Dyce; Diaby.