MILLWALL lost at home in the league for the second time this season as Bolton won 2-0 at The Den on Tuesday night.
Sammy Ameobi put Bolton ahead in the third minute with a shot from outside the box that eluded Jordan Archer's fingertips.
Millwall came close to equalising in the first half when Steve Morison flicked Shaun Williams' free-kick towards goal but Mark Howard was standing in the right place to make the save.
Archer then palmed away Zach Clough's drive, before Ben Thompson and Calum Butcher headed difficult chances over the crossbar.
Mahlon Romeo had to show his pace just before the break to seal off the danger after a Bolton break had left him exposed to Clough's threat.
Millwall dominated the game after the break, but they couldn't force Howard into a meaningful save as an obdurate Bolton added a second in the 86th minute when David Wheater volleyed home.
Bolton had come into the game having kept three successive clean sheets, but Millwall had scored in their previous 25 games.
Mark Beevers, who was booed after rejecting a Millwall contract to sign for Bolton in the summer, had said during the week "it doesn't matter how many we score as long as we keep the back door shut", and that was an apt description of the first half.
Millwall would surely have emphasised defending set-pieces against a team with four players over 6ft 3ins and in the second minute they looked to have cleared the danger from a corner. But then there seemed to be a collective flicking off of the switch, and Ameobi was left in too much space 25 yards out to fire high past Archer.
Harris had picked the same side that defeated Northampton 3-1 at the weekend, with Thompson on the left of midfield.
Most of the threat in the first half, though, came down the right side where the pace of Fred Onyedinma and Romeo unsettled Phil Parkinson's side.
Bolton were comfortable shuttling back into their own box as Millwall attempted to work opportunities to cross. Beevers would have warned his team-mates about the aerial threat of Morison and how to counter it, and when Tom Thorpe went off injured Derik Osede came on to perform that same defensive role in front of his centre-backs.
Morison appealed at one point to referee Darren Deadman that he was being impeded by Osede and Wheater, but there was little space for Millwall's top scorer or Lee Gregory to negotiate routes to goal. Morison will feel he should have scored when for once he was left free to get his head to Williams' free-kick, but he couldn't divert the ball either side of Howard.
Bolton continued to funnel Millwall attacks into the wide areas where they felt confident they had enough defensive cover and nous to cope. Soon after Jay Spearing shepherded Morison's ball towards Thompson over the line and wide, Harris replaced the midfielder with Aiden O'Brien.
It was mostly being played in Bolton's half at this point, but an away defender always appeared to block as a Millwall attacker attempted to get a shot away. Gregory was being particularly closely watched.
Harris brought on David Worrall and Shane Ferguson for Onyedinma and Joe Martin with just under 20 minutes left. Onyedinma had done well but perhaps Harris felt his side needed earlier deliveries from wide areas. When Tony Craig found space to shoot he saw his effort cleared and then the ball wouldn't drop quickly enough for Byron Webster to make a connection in the box.
For all Millwall's ascendancy they still hadn't really troubled Howard since half-time, more territory failing to translate into clear-cut chances.
The Den supporters optimistically hoped for a penalty when O'Brien went down in the box, but Bolton were far too canny to offer their opponents a free shot on goal.
Frustration rose among the home fans who felt Deadman was giving too many free-kicks to the visiting side. From one Bolton were able to get the ball down the pitch and win a corner. And it will be a source of huge annoyance that it was from that source – another set-piece – that Wheater scored, though the big centre-back deserved credit for the way he drilled his volley low into the corner past Archer.
Millwall claimed another penalty in added time when the ball seemed to strike a Bolton hand in the box, but Deadman waved away the appeals.
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