Wigan Athletic manager Uwe Rosler says his side "folded and gave up" during Friday's 3-1 defeat at Bolton.
The Latics, who conceded three goals in 11 second-half minutes, have just one victory in the last 12 and sit above the Championship relegation zone on goal difference.
"I take responsibility. But I have to be truthful, we didn't have the character," said Rosler.
"You cannot talk around that. I am not mentioning any individuals."
Goals from Max Clayton, Craig Davies and Lee Chung-yong helped lift Bolton out of the bottom three, with Callum McManaman scoring a late consolation for Wigan.
The 2013 FA Cup winners finished fifth in the Championship in 2013-14, but have won only three league matches after 17 games so far this season.
"The worst thing is that we have delivered such a performance in a derby game," Rosler added.
"I am not sure that means a lot for some of my players. I saw a lot today. Some of the players will have to wait a very long time before they get a chance again.
"I feel embarrassed. I apologise to the fans and the chairman for our performance in the second half."