Match ends, Millwall 1, Huddersfield Town 3.
Huddersfield overcame Nahki Wells' sending off to beat Millwall.
The Terriers were down to 10 men early in the second half when the striker was shown his second yellow card.
Sean Scannell's neat finish had put the Yorkshire club ahead, but Stefan Maierhofer cancelled it out before half-time.
Jacob Butterfield gave Huddersfield the lead again from long range, and a late penalty from James Vaughan sealed the three points for Chris Powell's side.
Millwall remain in the bottom three having extended their winless run at the New Den to nine games.
But hopes they would follow their victory at Nottingham Forest last time out with three crucial points at home came to nothing despite a good start, where Maierhofer hit the woodwork early on.
Huddersfield had gone close to opening the scoring when Millwall's Jos Hooiveld cleared the ball off his own line, but they were ahead seconds later.
Scannell's smart finish gave Huddersfield the lead, but it lasted little more than 10 minutes when a clearance from David Edgar struck Maierhofer and looped into the Huddersfield net.
Harry Bunn's curling shot hit the bar and Wells forced a good save out of Millwall goalkeeper David Forde as Huddersfield finished the first half strongly.
A poor challenge on Shaun Williams gave Wells his second booking in the 50th minute, but the away side responded well to the setback.
Having absorbed considerable Millwall pressure Huddersfield seized their chance, with Butterfield's long range shot having too much venom for Forde to hold on.
Bunn was brought down in the box with six minutes remaining, and Vaughan sent Forde the wrong way from 12 yards to condemn Ian Holloway's side to their eighth home defeat of the season.
Millwall manager Ian Holloway: "After the second goal everything went wrong, everything. It showed our lack of confidence. Sometimes things happen to keepers, where was the rest of the team to pick him up? Where was the rest of the team to pick up Jimmy Abdou when he fell over?
"Even against 10 men we should be doing our job to make sure we stay with our men. We just need to keep faith in what we are doing and the group needs to find more leaders.
"For some reason at the moment in this ground we're not really enjoying ourselves."
Huddersfield manager Chris Powell: "We knew we had to take something from the game and that was quite easily my best performance as manager.
"Considering we went down to 10 men, this team, which has showed a lot of togetherness recently, put in a very good performance against the odds.
"When we went down to 10 men we felt that if we kept our shape we could keep up with Millwall and we did."
- 1FordeBooked at 23mins
- 6WilliamsBooked at 30mins
- 15UpsonBooked at 22minsSubstituted forGregoryat 68'minutes
- 18GueyeSubstituted forWoolfordat 77'minutes
- 42MaierhoferSubstituted forFullerat 68'minutes
- 2EdgarBooked at 56mins
- 15M WallaceBooked at 55mins
- 30BunnSubstituted forGobernat 90+2'minutes
- 21WellsBooked at 51mins
- 9VaughanSubstituted forMillerat 89'minutes
- Mike Jones
- Shots on Target
Second Half ends, Millwall 1, Huddersfield Town 3.
Attempt missed. Martyn Woolford (Millwall) left footed shot from the centre of the box is too high. Assisted by Shaun Cummings with a headed pass.
Corner, Millwall. Conceded by Mark Hudson.
Attempt blocked. Ricardo Fuller (Millwall) header from the centre of the box is blocked. Assisted by Shaun Williams.
Mark Beevers (Millwall) wins a free kick in the attacking half.
Foul by Jacob Butterfield (Huddersfield Town).
Substitution, Huddersfield Town. Oscar Gobern replaces Harry Bunn.
Shaun Cummings (Millwall) wins a free kick in the defensive half.
Foul by Ishmael Miller (Huddersfield Town).
Corner, Huddersfield Town. Conceded by Jos Hooiveld.
Foul by Jos Hooiveld (Millwall).
Ishmael Miller (Huddersfield Town) wins a free kick in the defensive half.
Substitution, Huddersfield Town. Ishmael Miller replaces James Vaughan.
Shaun Williams (Millwall) wins a free kick in the defensive half.
Foul by James Vaughan (Huddersfield Town).
Martyn Woolford (Millwall) wins a free kick on the left wing.
Foul by Sean Scannell (Huddersfield Town).
Goal! Millwall 1, Huddersfield Town 3. James Vaughan (Huddersfield Town) converts the penalty with a right footed shot to the bottom right corner.
Penalty conceded by Shaun Williams (Millwall) after a foul in the penalty area.