Adrian Lam said he was proud of his players despite seeing them throw away a 20-0 lead to crash to a 38-28 loss at Castleford.
Wigan blazed into a 20-0 lead by midway through the first-half and led 24-8 by half-time.
But their young pack tired as re-energised Castleford roared back to edge a nip-and-tuck second-half.
The Warriors' cause was hampered by the loss of Jarrod Sammut, Dom Manfredi and Joe Greenwood to injury, forcing many of the players to motor through longer spells.
And Lam said: "I thought we were brilliant in the first-half and completing at 90 per cent - that was the ideal half.
"We put ourselves in a position to win the game but in the second half, fo 17 minutes we didn’t touch the ball.
"We had a lot of young players and we knew they'd be under the pump at some stage. There were a couple of soft tries there... we had one sub with 30 to go.
"So I'm proud of their efforts. The boys there were courageous."
A win would have moved Wigan up to fifth behind Wakefield, who are the Warriors' next opponents on Friday.
"I’m really happy with how we’ve improved over the last month. We’re heading in the right direction," said Lam.