MILLWALL boss Neil Harris admitted his side's performance in the first half against Colchester was "lacklustre" after a tense 0-0 draw at Weston Homes Community Stadium.
Lee Gregory missed two chances before the break and Chris Taylor couldn't beat Elliott Parish after directing the striker's cross towards goal.
Harris brought on Shane Ferguson at half-time for Aiden O'Brien, who had struggled to match his performance against the Brewers.
Millwall improved in the second period and Gregory almost give his side the lead on the hour when he ran onto Steve Morison's flicked header but from a difficult angle he couldn't find a way past Parish who saved.
Taylor also saw his shot in the penalty area take a deflection before coming back off the bottom of the post with Parish beaten.
Colchester also had their chances. Jordan Archer had to get down quickly to his left to keep out Elliot Lee's shot in the first half.
Striker Chris Porter also saw a half-volley just clear the crossbar and had a header saved by Archer.
Lee was Colchester's most threatening player as they pushed for a winner, while Ben Thompson moved forward to the edge of the box to shoot, but Parish was again well positioned to make the stop.
Harris was disappointed that his side didn't match their performance against Burton, but felt they still created enough good chances to have won the game.
"It's frustrating but the effort is there and the desire is there," Harris said. "But I was very disappointed with a really lacklustre first half.
"Having said that, we had some really good chances to score.
"The second half we made an adjustment and put Fergie in on the left-hand side. I thought we put a lot of good balls into the box and got into a lot of good positions, but we just didn't have that killer touch in the box.
"It was the width of the post that cost us in the end, but it was a disappointing result."
Harris also praised Colchester, who had won their last two fixtures before keeping just their third clean sheet in their last 30 league games and leave the Millwall boss with the feeling that this was two points dropped.
"I saw Colchester the other night at Coventry and they played really well and deserved to win the game," Harris said. "They have some really good attacking players and they have momentum.
"But having said that, with the form we are in, we should have done better.
"We had three chances in the first half and one in the second, that's four clear-cut chances. And we hit the post.
"We certainly could have won the game but I thought Colchester defended really well."