NEIL Harris paid tribute to Bolton's defensive performance as his side were left frustrated in their attempts to capitalise on their second-half territorial dominance at The Den on Tuesday night.
Bolton took an early lead through Sammy Ameobi's long-range drive before they defended stoutly on the edge of their own box for the majority of the second period.
Mark Beevers was booed by Millwall fans throughout, but he led a commanding defensive display to protect goalkeeper Mark Howard, who was rarely troubled.
And Beevers' central defensive partner David Wheater made the points safe when he volleyed home a second goal late on.
"I thought they defended really well, fair play to Bolton, they defended their box exceptionally well," Harris said. "They scored two really good goals, not going to fault anyone, the finishes were excellent, top drawer.
"But it's the build-up to the corners we conceded for the two goals, we've got to be better. Then again for a home performance I thought we were really good for 70 minutes, barring the last 10 minutes and the first 10 minutes where we didn't quite find our feet.
"It's the second game running we're the same, excellent for 70 minutes but the boys have to realise they have to do it for 90 minutes.
"I wouldn't say we got punished tonight, we got punished for errors in previous weeks, tonight it was just really good goals."
It was the first time in 26 games in all competitions that Millwall had failed to score, with Bolton registering a fourth successive clean sheet to remain in third place in the table.
Millwall are now just outside the relegation zone after failing to find a way past a physical and stubborn defence.
And Bolton boss Phil Parkinson felt Beevers was key to his side's victory.
"I thought he was outstanding," Parkinson said of Beevers' performance. "The two at the back for us were a colossus. Beevs has just continued his form from the way he has been playing.
"But it's always a test when you come back to your old club because he loved his time here. The supporters gave him a bit of stick tonight, which you're always going to get, but they appreciated his efforts while he was here.
"I thought we were disciplined and everybody did the job for the team. We said to the lads that coming to Millwall you've got to stand strong.
"I've played here before and managed teams here before and got beaten. I've watched games where teams don't stand strong and are two- or three-nil down before they've realised they're in a game.
"We knew what we had to do and to be fair to the lads they did it to the letter."
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