Michael Appleton oversaw his first win as Blackburn manager as they eased into the fifth round of the FA Cup with victory at Derby.
Colin Kazim-Richards pounced on a defensive error to fire Rovers ahead shortly before the break.
The visitors had the better chances in the second half and Scott Dann volleyed in a second just after the hour.
Jordan Rhodes completed the scoring for Blackburn soon after, lifting the ball over the Derby keeper.
For the first 40 minutes or so the game was hardly an FA Cup classic, with both sides creating very little.
It took until the 26th minute for a chance on goal to materialise as Morten Gamst Pedersen's powerful free-kick was pushed away by Derby goalkeeper Adam Legzdins.
The opening goal arrived a minute before the break as Richard Keogh missed his clearance from a long ball by Jason Lowe and Kazim-Richards reacted quickly to race through and fire beyond Legzdins.
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Blackburn's win ended a run of four successive away defeats in previous FA Cup competitions.
Derby managed their first chance on goal just before the half-time whistle as John Brayford volleyed weakly at Jake Kean.
The home side's struggles to work the Blackburn defence continued in the second half, but they should done better just before the hour when Jamie Ward found space, only to fire weakly at Kean.
Blackburn added a second in the 66th minute through Dann, who was picked out by Danny Murphy and the defender rifled a volley into the net.
Derby were just recovering from that strike when Blackburn scored a third to end the game as a contest. The excellent Marcus Olsson fed a pass to Rhodes, who lifted the ball over the Derby keeper for his 17th goal in a Blackburn shirt.
The hosts had a chance to snatch a consolation eight minutes from time but Jeff Hendrick headed wide.
Derby manager Nigel Clough:
"Blackburn were a bit too good for us although there was nothing in it until we paid for a bad mistake with their first goal just before the break.
"After that, their experience and physical strength shone through and our young lads found them hard to handle.
"Jordan Rhodes and Colin [Kazim] Richards are as big a handful as any attacking partnership at our level and it was also a tough task for our kids to come up against a player like Danny Murphy in midfield."
Blackburn manager Michael Appleton:
"I'm delighted to be making progress in the competition but I still believe we need to bring in a couple more players before next Thursday's [transfer] deadline if possible. There is still plenty to play for in the league and areas where I would like to see us being able to call on reinforcements.
"I don't have a budget as such but I am sure the owners would support me if I went to them with a viable deal for the right players.
"Victory is all-important in the cup but keeping a clean sheet at a place like Pride Park is also a big plus for us. I believe in trying to build a platform and a structure that makes it hard for the opposition to score or get behind us and there were very pleasing signs of that sort of shape developing."
Morten Gamst Pedersen takes a outswinging corner to the near post.
Ruben Rochina fouled by Gareth Roberts, the ref awards a free kick. Ruben Rochina restarts play with the free kick.
Ruben Rochina takes a shot. Save by Adam Legzdins. Corner from the right by-line taken by Morten Gamst Pedersen, John Brayford manages to make a clearance.
Grant Hanley concedes a free kick for a foul on Paul Coutts. John Brayford takes the direct free kick.
Substitution Markus Olsson leaves the field to be replaced by David Dunn.
Substitution James O'Connor comes on in place of Mark O'Brien.
Ben Davies restarts play with the free kick.
Booking The referee shows Ruben Rochina a yellow card.
Ruben Rochina gives away a free kick for an unfair challenge on Gareth Roberts.
Colin Kazim-Richards concedes a free kick for a foul on Mark O'Brien. Gareth Roberts takes the direct free kick.
Michael Jacobs gives away a free kick for an unfair challenge on Martin Olsson. Jake Kean takes the free kick.
Substitution Ben Davies comes on in place of Will Hughes.
Corner taken left-footed by Morten Gamst Pedersen, Grant Hanley takes a shot. Blocked by Gareth Roberts.
Substitution Michael Jacobs joins the action as a substitute, replacing Jamie Ward.
The assist for the goal came from Markus Olsson.
70:37 Goal scored
Goal! - Jordan Rhodes - Derby 0 - 3 Blackburn Jordan Rhodes grabs a goal from inside the box to the top left corner of the goal. Derby 0-3 Blackburn.
Free kick awarded for an unfair challenge on Ruben Rochina by Jamie Ward. Morten Gamst Pedersen delivers the ball from the free kick left-footed from right channel, Gareth Roberts manages to make a clearance.
The assist for the goal came from Danny Murphy.
65:34 Goal scored
Goal! - Scott Dann - Derby 0 - 2 Blackburn Scott Dann fires in a goal from deep inside the penalty box to the top right corner of the goal. Derby 0-2 Blackburn.
Ruben Rochina takes a shot. Adam Legzdins makes a save. Corner taken left-footed by Morten Gamst Pedersen from the right by-line, clearance made by Gareth Roberts.
The offside flag is raised against Jordan Rhodes. John Brayford restarts play with the free kick.
Adam Legzdins restarts play with the free kick.
Booking Markus Olsson goes into the book for unsporting behaviour.
John Brayford fouled by Markus Olsson, the ref awards a free kick.
Ruben Rochina has an effort at goal from long distance that goes wide left.
Jamie Ward decides to take a short corner.
Ruben Rochina produces a left-footed shot from just outside the area that goes wide left of the goal.
Free kick awarded for a foul by Ruben Rochina on Jamie Ward. Jamie Ward delivers the ball from the free kick right-footed from left channel, save by Jake Kean.
Jamie Ward is penalised for a handball. Jake Kean restarts play with the free kick.
Inswinging corner taken left-footed by Morten Gamst Pedersen from the right by-line.
Free kick awarded for an unfair challenge on Ruben Rochina by Gareth Roberts. Grant Hanley takes the free kick.
The match restarts for the second half.
45:00 +3:24 Half time
Half Time The referee blows for half time.
Paul Coutts takes the free kick.
45:00 +1:23 Booking
Booking Booking for Grant Hanley for unsporting behaviour.
Foul by Grant Hanley on Craig Bryson, free kick awarded.
Jason Lowe provided the assist for the goal.
43:48 Goal scored
Goal! - Colin Kazim-Richards - Derby 0 - 1 Blackburn Colin Kazim-Richards grabs a goal from inside the penalty box low into the middle of the goal. Derby 0-1 Blackburn.
Will Hughes decides to take the corner short.
Colin Kazim-Richards is ruled offside. Indirect free kick taken by Adam Legzdins.
The assistant referee signals for offside against Conor Sammon. Indirect free kick taken by Grant Hanley.
Colin Kazim-Richards concedes a free kick for a foul on Jeff Hendrick. Gareth Roberts takes the free kick.
Free kick awarded for an unfair challenge on John Brayford by Martin Olsson. Free kick taken by Paul Coutts.
Corner taken left-footed by Morten Gamst Pedersen, clearance by Paul Coutts.
Jamie Ward concedes a free kick for a foul on Morten Gamst Pedersen. Direct free kick taken by Jake Kean.
Free kick awarded for an unfair challenge on Will Hughes by Colin Kazim-Richards. John Brayford takes the direct free kick.
Free kick awarded for an unfair challenge on Markus Olsson by Paul Coutts. Direct strike on goal from the free kick comes in from Morten Gamst Pedersen, save by Adam Legzdins.
Inswinging corner taken from the right by-line by Morten Gamst Pedersen, Conor Sammon manages to make a clearance.
Outswinging corner taken from the right by-line by Paul Coutts, Jason Lowe makes a clearance.
Martin Olsson is penalised for handball and concedes a free kick. Will Hughes restarts play with the free kick.
Free kick awarded for a foul by Martin Olsson on John Brayford. Free kick crossed left-footed by Will Hughes from right channel, Scott Dann makes a clearance.
Corner taken by Jeff Hendrick, Grant Hanley manages to make a clearance.
Substitution Ruben Rochina joins the action as a substitute, replacing Joshua King.
The referee penalises Paul Coutts for handball. Morten Gamst Pedersen produces a cross, Grant Hanley has a headed effort at goal from close in which goes wide left of the goal.
Jeff Hendrick gives away a free kick for an unfair challenge on Danny Murphy. Direct free kick taken by Morten Gamst Pedersen.
Grant Hanley challenges Conor Sammon unfairly and gives away a free kick. Paul Coutts restarts play with the free kick.
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