Match ends, Derby County 3, Rotherham United 0.
Derby County extended their unbeaten Championship run to nine games with victory over Rotherham United.
Andreas Weimann poked in his first goal for the Rams from six yards to give Paul Clement's side an early lead.
Midfielder Jacob Butterfield then opened his account for Derby with a long-range shot on the stroke of half-time to double their advantage.
Chris Martin hit the bar with a free-kick for the Rams before Richard Keogh lashed in a third to seal the points.
Derby have not lost since being beaten by Leeds at the iPro Stadium on 29 August, and have now won seven games during their unbeaten run to climb to fifth and within a point of the automatic promotion places.
Rotherham, meanwhile, slipped to the bottom of the table ahead of Bolton's evening kick-off at Preston and are yet to win in four matches under new boss Neil Redfearn.
Derby needed only seven minutes to take the lead when Butterfield and Craig Forsyth combined to set up Weimann, replacing the injured Tom Ince, and the former Aston Villa striker stabbed into the roof of the net.
Jonson Clarke-Harris forced a couple of saves from Derby keeper Scott Carson as Rotherham sought an equaliser, only for Butterfield's shot from distance to give Derby control.
Weimann saw a lob cleared off the line as they continued to dominate, and after Martin had hit the bar, Keogh fired home his first goal since December 2013 from close range to wrap up a convincing win.
Derby manager Paul Clement:
"I am learning about my players all the time. They are showing so many different qualities now, whether it be the team spirit or dealing with different styles of football.
"The momentum is really building and we are enjoying the way we are playing and we are full of confidence.
"I had some concerns going into the game, but it was a solid afternoon from start to finish. We had a really good start and we controlled the game and finished the half strongly."
Rotherham boss Neil Redfearn:
"That was not acceptable. I accept the odd mistake now and again but not the lack of work-rate and wanting to win and that was apparent today.
"Players have got to take responsibility. You put a game plan together and they go out there, it's up to the players to take the bull by the horns, and once we let them get in their stride we never laid a glove on them and that is really disappointing.
"They were worthy 3-0 winners to be honest. We have got a lot of work to do, we have got to bring some players in, that's a fact."
- 18ButterfieldSubstituted forBrysonat 79'minutes
- 34ThorneBooked at 33minsSubstituted forHendrickat 63'minutes
- 9MartinSubstituted forBentat 77'minutes
- 3MattockBooked at 49mins
- 33SmallwoodBooked at 26mins
- 22NewellSubstituted forGreenat 45'minutes
- 30ToffoloSubstituted forWhiteat 62'minutes
- Scott Duncan
- Shots on Target
Second Half ends, Derby County 3, Rotherham United 0.
Foul by Jeff Hendrick (Derby County).
Grant Ward (Rotherham United) wins a free kick in the defensive half.
Attempt blocked. Jeff Hendrick (Derby County) right footed shot from outside the box is blocked. Assisted by Andreas Weimann.
Foul by Andreas Weimann (Derby County).
Danny Collins (Rotherham United) wins a free kick in the defensive half.
Foul by Craig Forsyth (Derby County).
Paul Green (Rotherham United) wins a free kick in the defensive half.
Offside, Derby County. Johnny Russell tries a through ball, but Darren Bent is caught offside.
Jeff Hendrick (Derby County) wins a free kick in the attacking half.
Foul by Richard Smallwood (Rotherham United).
Jason Shackell (Derby County) hits the bar with a header from the centre of the box. Assisted by Johnny Russell with a cross following a corner.
Corner, Derby County. Conceded by Joe Mattock.
Substitution, Derby County. Craig Bryson replaces Jacob Butterfield.
Attempt blocked. Jonson Clarke-Harris (Rotherham United) left footed shot from the right side of the box is blocked. Assisted by Grant Ward.
Substitution, Derby County. Darren Bent replaces Chris Martin.
Goal! Derby County 3, Rotherham United 0. Richard Keogh (Derby County) right footed shot from the centre of the box to the high centre of the goal following a corner.
Corner, Derby County. Conceded by Danny Collins.
Chris Martin (Derby County) hits the bar with a right footed shot from outside the box from a direct free kick.