Two goals from Junior Mendes were enough to see Huddersfield Town end Luton's unbeaten start to the league season.
The Hatters had won six out of six at home before the visit of the Terriers, but two first-half Mendes strikes proved to be enough to stop them matching the club's record unbeaten start to a season set in 1969-70.
Paul Underwood gave Luton hope with a second-half curler and Steve Howard hit the post, but it wasn't enough.
Luton stated their intentions from the off with some neat passing football and after Michael Leary's eighth minute shot was deflected wide, Howard saw a header bounce off Efe Sodje and just over the bar.
Ahmet Brkovic picked up his fifth booking of the season - and a one match ban – two minutes later for a foul on Chris Brandon.
And the hosts were shocked further in the 14th minute when Jon Worthington played in Mendes on the left and the striker turned inside Kevin Foley and unleashed a screamer into the far corner from outside the area to give the Terriers the lead.
The visitors almost made it two in the 23rd minute when Pawel Abbott somehow danced his way past three Luton defenders in the penalty area and squared to Anthony Lloyd, who fired over from 10 yards.
Sol Davis powered a free header over the bar from 12 yards for Luton from Leary's pinpoint cross from the right in the 32nd minute.
And that miss looked to have proved costly when Tony Carss' 34th minute corner was flicked home by Mendes to make it 2-0.
Luton hit back when Underwood's 42nd minute cross from the left was nodded back by Howard for Curtis Davies to head goalwards and the ball bounced off the face of visiting goalkeeper Ian Gray before being smothered.
Substitute Gary McSheffrey almost made an immediate impact when his 22-yard free-kick in first-half stoppage time was superbly tipped around the post by Gray.
From Brkovic's resulting corner, Davies was unfortunate to see his close-range header go the wrong side of the post.
Luton finally got back into the game when Rowan Vine played in Underwood on the right and the ex-Diamonds man turned and curled home a beauty with his left foot, in off the post from 15 yards for his third of the season.
Chris Coyne then thumped in a header from Kevin Nicholls' 67th minute free-kick, but his effort was pushed away by Gray.
The Hatters kept up the pressure and Howard looped a 71st minute header that hit the post and from the rebound Brkovic smashed over from eight yards.