Goals from Elias Kachunga and Nahki Wells sent Huddersfield back to the top of the Championship as they beat Rotherham, who slipped to the bottom.
Kachunga gave his side an early lead when he poked in from close range after sustained pressure from the Terriers.
Rotherham equalised through Danny Ward’s volley, but Wells’ shot restored the hosts’ advantage before the break.
Huddersfield were rarely tested after half-time as they went two points clear of Norwich City at the summit.
Tom Adeyemi did come close to drawing Rotherham level for a second time when he headed wide at the back post late on, but the visitors managed only one shot on target throughout the game.
The Millers are now without a win in six league games, having conceded 24 goals this season, four more than any other team.
Huddersfield, meanwhile, have won seven of their opening 10 games, but could fall to second if Norwich beat Newcastle at St James’ Park on Wednesday.