Jake Cooper felt Millwall did not produce a “perfect” mentality in Tuesday’s 2-2 draw with Wigan Athletic.
The Lions extended their unbeaten run to three Championship matches but twice had to come from behind against Paul Cook’s side.
Wigan came into the contest in poor form – only Luton had taken fewer points in their last five league games. The Latics had drawn one and lost the rest before arriving in SE16.
Cooper said: “It was a poor start. The mentality was maybe a little bit not perfect after the win on Saturday.
“We were a bit over-confident, you could say. We didn’t do the little things as well as we normally do. You need to come out and perform to the best of your ability in every game in this league.
“Wigan went out there and did the little things a bit better than us. They made it tough for us – they played direct. Maybe they’ve had something to prove. They’ve given away a few late goals and they went for it, putting two strikers up against us. Credit to them.
“They probably deserved it a little more than we did but we’re proud of the fact we could come back twice and get a point to keep our confidence high going into the game on Saturday.”
Millwall head to Birmingham tomorrow – and have won their last three trips to St Andrews and not conceded a goal.
The Lions picked up their first away victory of the season last weekend with Jed Wallace’s free-kick defeating Swansea.
Millwall boss Gary Rowett switched to a 5-2-3 formation in South Wales.
“We really felt we dominated that game and could have won 2-0 or 3-0,” said Cooper. “We certainly take a lot of confidence out of that.
“The formation we played, the boys really enjoyed it. We felt the benefits of it. We’re looking forward to trying to back that up on Saturday.
“You could say it gives us more stability [with an extra centre-back] but I think it was just more of a psychological thing for the players to try something different.
“It gave us new spaces to get into with the ball. Players were getting more time on the ball and we were creating more dangerous opportunities.”