IAN Holloway believes his half-time substitution during Saturday's 2-0 defeat to Ipswich Town contributed to Millwall's flat display.
The Lions manager withdrew holding midfielder Jack Powell and brought on winger Magaye Gueye, with Martyn Woolford moving into a central position in the middle of the park.
But, speaking ahead of tonight's Championship clash at Reading, Holloway admitted his side got "progressively worse and worse" after he made that change.
He said: "I made a mistake at half time. I should have changed Ed Upson for Powell, rather than move Woolford, who was dealing with Tyrone Mings. I just got it wrong.
"I put Magaye on to give us a pass because we were that close to being half-decent, but Mings came more into the game. I've looked back at it because I always buy neurontin analyse what I do.
"Woolford was dealing with Mings for me and I could always have put Magaye on later in the game. I've realised that watching the game back."
Despite recognising his error, Holloway felt Millwall's players were still lacking their usual intensity and aggression.
"We've stopped doing what we were really good at which was pressing, closing down and getting organised," he said.
"Their two banks of four out-did ours in the second half.
"Progressively I felt we got worse and worse, but let's learn from it and move onto the next one.
"Our second-best chance came from us winning the ball back from their throw-in, Mathias Ranegie played in Woolford but we didn't score.
"Their best chance came from them winning the ball back from our throw-in, and they scored. That's how tight it was."