Match ends, Millwall 0, Burton Albion 1.
Burton Albion moved out of the Championship relegation zone after recording their first away league win of the season at 10-man Millwall.
Millwall had the upper hand until Jed Wallace was shown a straight red card for a foul on Tom Flanagan with 32 minutes remaining.
Burton took advantage as Marvin Sordell scored to end a run of seven league games without a win.
The Lions almost grabbed a point after Lee Gregory hit the post in added time.
The hosts had the better of what was a scrappy encounter in the first half, and should have been ahead at break through Aiden O'Brien, who blasted over from four yards out just before the interval.
The game changed after Wallace became the fourth Millwall player to be sent off this season when he was harshly dismissed by referee Tony Harrington for a challenge from behind on Flanagan on the halfway line.
Sordell then stabbed in Matty Palmer's centre from close range to net the visitors' first Championship goal away from home since 12 August - a drought which lasted six matches.
Nigel Clough's side leapfrog Sunderland, who face Middlesbrough on Sunday, and Birmingham to move one point ahead of the Blues.
Millwall, who had won four of their previous five home games, have now suffered three defeats at The Den this season and are now 19th, five points above the bottom three.
Millwall manager Neil Harris told BBC Radio London:
"I'm frustrated and disappointed with the outcome.
"We missed two guilt-edged chances in the first half and our attacking players have not done enough in the penalty area, so we need to address that.
"The red card changes the complexion of the game and gave Burton more inspiration and bravery. I've not seen it again properly but at the time I was amazed and I think the whole ground was astonished.
"You see forty of those challenges every weekend up and down the country and they are not red cards. It is a late tackle but if you give a red for those challenges you'll soon end up with nine versus nine or a non-contact sport."
Burton manager Nigel Clough:
"We're extremely relieved. We've played much better and got no points, but sometimes you get your rewards when you don't necessarily deserve them.
"We were surprised [about the red card], but I haven't seen the tackle back so I don't know how high it was.
"We've got a lot more decisions that need to come our way if it's going to even out from the first 15 games.
"It was nice for Marvin to play and score. Its a much of a muchness between him and Lucas Akins, but Marvin is the one that needs the least number of chances to get a goal."
- 3MeredithBooked at 45minsSubstituted forOnyedinmaat 87'minutes
- 14J WallaceBooked at 58mins
- 22O'BrienSubstituted forThompsonat 64'minutes
- 20MorisonSubstituted forElliottat 64'minutes
- 1BywaterBooked at 88mins
- 6TurnerBooked at 74mins
- 12FlanaganSubstituted forWarnockat 72'minutes
- 9ScannellSubstituted forAkinsat 64'minutes
- 17SordellSubstituted forVarneyat 83'minutes
- Tony Harrington
- Shots on Target
Second Half ends, Millwall 0, Burton Albion 1.
Lee Gregory (Millwall) hits the right post with a right footed shot from the right side of the box.
George Saville (Millwall) wins a free kick on the right wing.
Foul by Luke Murphy (Burton Albion).
Attempt missed. Lloyd Dyer (Burton Albion) left footed shot from the left side of the box misses to the right. Assisted by Matthew Palmer.
Foul by Tom Elliott (Millwall).
Ben Turner (Burton Albion) wins a free kick in the defensive half.
Stephen Bywater (Burton Albion) is shown the yellow card.
Substitution, Millwall. Fred Onyedinma replaces James Meredith.
Substitution, Burton Albion. Luke Varney replaces Marvin Sordell.
George Saville (Millwall) wins a free kick on the left wing.
Foul by Kyle McFadzean (Burton Albion).
Attempt missed. Ryan Tunnicliffe (Millwall) right footed shot from outside the box is too high. Assisted by James Meredith.
Attempt missed. Shaun Hutchinson (Millwall) header from the centre of the box misses to the right. Assisted by George Saville with a cross following a set piece situation.
Ben Turner (Burton Albion) is shown the yellow card for a bad foul.
Lee Gregory (Millwall) wins a free kick in the attacking half.
Foul by Ben Turner (Burton Albion).
George Saville (Millwall) wins a free kick in the defensive half.
Foul by Matthew Lund (Burton Albion).