Sheffield Wednesday denied Huddersfield a return to the top of the Sky Bet Championship with a 1-0 win at the John Smith's Stadium.
Fernando Forestieri's second-half penalty was enough to separate the sides in a thunderous Yorkshire derby played out in front of a crowd of 22,368 - Huddersfield's biggest league attendance on this ground.
Wednesday's second away win of the season boosts their own promotion aspirations, with the Terriers failing to win at home for the first time this season.
The hosts were without injured pair Joe Lolley and Sean Scannell, so David Wagner brought in Kasey Palmer and Rajiv van La Parra.
Sheffield Wednesday manager Carlos Carvalhal made four changes to the side beaten by Brighton on home soil last time out, with David Jones, Liam Palmer, Sam Hutchinson and Gary Hooper all handed starts.
The visitors started at a frantic pace, with Forestieri getting clear down the left in the fourth minute and his cut back eventually falling for Kieran Lee, whose effort deflected behind.
From the resulting Jones corner Daniel Pudil missed a good chance at the back post, and when the ball was worked back out to Jones on the right the former Burnley midfielder's cross cannoned back off the crossbar.
Huddersfield grew into the game, with Aaron Mooy pulling the strings in midfield.
Nahki Wells found space down the left after 11 minutes but Elias Kachunga could not get enough purchase on his header.
Chris Lowe's 20th-minute corner was only cleared as far as Australian Mooy, whose powerful 25-yarder fizzed over the bar.
Palmer and Van La Parra combined down the left on 31 minutes, with the latter picking out Kachunga only for Keiren Westwood to keep out his low effort.
Two minutes later Palmer cut inside from the right and Westwood had to be at his best to parry a low 20-yarder round the post.
Four minutes after the break Forestieri was sent scampering clear, but although his delicate finish beat keeper Danny Ward it bounced back off the face of the post.
Forestieri smashed in the opener in the 67th minute from the penalty spot after Van La Parra used his hand to block a Tom Lees effort.
Mooy fired a free-kick over and substitute Jack Payne saw his effort headed over the bar as the hosts tried to respond, while at the other end Lee picked out Hooper at the back post but he could not direct his header on target.
Lee headed Kachunga's effort off the line with 10 minutes remaining, although the Owls survived comfortably after that and Tom Palmer should have wrapped up the points when he was played in by Hooper but shot straight at Ward.