Millwall boss Ian Holloway said his team were "dysfunctional" and their performance "unacceptable" after a 4-0 FA Cup replay defeat at Bradford.
The Lions would have secured a lucrative fourth-round tie with London rivals Chelsea with a win but were a man down inside six minutes.
"The lads don't look like a Millwall team, or my team - they didn't have any fight in them," Holloway said.
He stayed in the dressing room with players for an hour after the game.
"All I can do is apologise to the fans. I've never seen a team capitulate as badly as that," he added.
|Since beating Cardiff on 25 October, Millwall have won once in 13 games in all competitions.||They have scored 13 times in 13 games, but conceded 32 goals.|
|In that run, the Lions have drawn four times and lost eight games.||Ian Holloway has won 12 of 50 games since taking charge in January 2014.|
Millwall have won one of their last 13 games in all competitions and are in the relegation zone of the Championship.
After Mark Beevers' early red card, League One side Bradford scored through James Hanson, Jon Stead, Andy Halliday and Billy Knott to secure a trip to Stamford Bridge on 24 January.
Millwall face Ipswich in the league on Saturday but have not won at home since October, and Holloway said he was hurt to hear both sets of fans chanting "You're getting sacked in the morning" at Bradford.
"I've been doing it 19 years and 860-odd games, I said it would be tough when I came here, but I didn't think it would be as tough as this," he said.
"The pride that you should wear that shirt with, I didn't see. That's unacceptable.
"There's something wrong with the group, we're dysfunctional. That's what we've been talking about in the dressing room."