MARK Beevers pulled no punches after Millwall's 3-0 defeat to Leicester City.
The centre back admitted the Lions' defensive performance had not been good enough and that they "failed to adapt" to the Foxes' counter-attacking tactics.
Boss Steve Lomas had warned of the opposition's threat on the break before the game but time and time again Nigel Pearson's side were able to turn defence into attack.
Beevers said: "We knew Leicester would be a big test – every team in the league knows that – but we've got to be disappointed with the goals we have conceded. They were very much avoidable from our point of view.
"They've got bags of pace – the two wingers are rapid – but we knew that so it's not as if they took us by surprise. We didn't adapt to it and only have ourselves to blame."
Millwall's vulnerability to the counter-attack was epitomised by Jamie Vardy's 52nd-minute goal, which came directly after a clearance from a corner at the other end of the field.
"They broke from our corner, which they probably did ten times throughout the game, and that's not good enough," Beevers added.
"The first goal came from us not picking up a midfield runner and maybe we should have been tighter as a back four. Scott Malone made a mistake for the third which happens.
"Paul Robinson and I were chatting after the game and we thought we did reasonably okay in the first half against their strikers. We restricted them to mainly long shots.
"But after the third goal went in we were stretched. It's not good enough and we know that."
As the Lions' heads dropped, Leicester continued to pour forward and would have won by an even greater margin had goalkeeper David Forde not been in such impressive form.
Beevers said: "It's not easy to pick yourself up when you're 3-0 down at Leicester, but we're all professionals and we should be man enough to keep going and fight.
"Some people might think that we rolled over and they took the mick out of us a little bit, but the only positive is that we didn't concede a stupid amount of goals.
"Fordey made a lot of good saves but it was a very bad day at the office."
Lomas' side have the chance to make amends for such a poor performance when they host Nottingham Forest on Tuesday night.
"We've got to get back on the horse," Beevers said. "We responded to a big defeat to Derby earlier in the season and we are more than capable of doing the same again.
"It is an important game. We've been doing well at The Den recently so there is no reason why we can't turn over Forest. Things will be looking up again if we get a win."