BLACKBURN Rovers coasted into the fifth round of the FA Cup as Michael Appleton celebrated his first win as manager.
A first half strike from Colin Kazim-Richards gave Rovers the lead, before a second half wonder strike from Scott Dann and a poachers finish from Jordan Rhodes killed off a poor Derby County.
In a quiet first half, neither side looked particularly likely to break the deadlock.
Morten Gamst Pedersen went close with an inswinging free kick that was tipped over the bar by Legzdins, while Jordan Rhodes had a close range flick blocked.
At the other end, Derby looked impotent as an attacking force, with former Ram Jake Kean untested inbetween the posts.
The breakthrough came on 43. Kazim-Richards robbed a hestitant Richard Keogh, chasing on to a hopeful punt from Jason Lowe, and finished smartly underneath goalkeeper Legzdins.
The second half continued in a similar fashion with the hosts struggling to create much of note in an attacking sense.
Rovers goalkeeper almost gifted Derby a leveller with a sloppy clearance but he was at least alert enough to react and block Jamie Ward's shot.
Markus Olsson thought he had doubled the lead on 63, but Jordan Rhodes was ruled out for his part in the approach work.
Rovers didn't have long to wait and were 2-0 ahead on 66. Danny Murphy's clever chipped pass found Scott Dann on the edge of the penalty area and his dipping volley flew into the top corner.
The travelling faithful were in dream land five minutes later as Jordan Rhodes put Rovers even further ahead.
The Scot calmly lifted the ball over the Derby stopper after being played through by Markus Olsson.