Adrian Lam was "frustrated" but refused to criticise his players after Wigan went down 30-20 at Wakefield.
The defeat, their second in succession, leaves them two points above bottom-club Leeds after 10 rounds ahead of the Good Friday derby with St Helens.
Lam's side, missing nine frontline players, led 4-0 by the 36th minute but incredibly leaked three tries before half-time to trail 16-4 - and the hosts kept the Warriors at jabbing distance away in a second-half which saw Joe Shorrocks make his debut.
Lam said: "It's frustrating, with the side we had we competed pretty well for 35 minutes and then five minutes of mayhem turned the whole game.
"I was angry at half-time but at the end of the game I felt for them, we had two teenagers in there, a couple in new positions, Zak Hardaker withdrew for family reasons, we lost Tommy (Leuluai) at half-time... it disrupted the side.
"It's a tough one, we lost concentration at certain points but it's hard to get angry at the players when they're doing their best."
Joe Burgess finished with a hat-trick and Lam praised their attack in the second-half - but admitted the lapses in concentration proved too costly.
He will assess Leuluai's calf strain tomorrow.