Kevin Nugent praised a "spirited" performance from his Millwall Under 23s' side despite losing 1-0 to Ipswich Town on Monday afternoon.
The Professional Development League meeting looked to be heading for a goalless draw until Idris El Mizouni's long-range effort deep into stoppage-time won all three points for The Tractor Boys.
"That was a tough one to take," Nugent told millwallfc.co.uk. "I thought it was a good game, a very competitive game from both sides.
"They had a lot of first-team players in their side, but we needed to get something out of that game. We didn't, and the manner in which that came was a real kick in the teeth. However, the lads, individually, have put in a real spirited performance in difficult conditions."
The normally free-scoring young Lions have now failed to find the net for two games consecutively, and the boss challenged his players to "dust themselves down and get on with it" ahead of the next match - a London derby against Queens Park Rangers.
"We've been practising in training, doing bits and pieces, but in the final third today, whilst we got into good positions, the final touch or pass maybe bobbled away from someone. There weren't too many chances at either end, though, so a draw would've been a fair result.
"They've got to dust themselves down and get on with it. Their application is never in doubt. The conditions weren't ideal today, but there was some quality play in there."