Derby thrashed a lacklustre Watford to secure their first home win in more than five months.
Centre-back Richard Keogh glanced in a header and Jeff Hendrick also nodded home to give the Rams the upper hand.
Conor Sammon chipped a delightful shot over keeper Manuel Almunia to extend Derby's lead.
Will Hughes and Jamie Ward both tapped in to put the game beyond doubt before Matej Vydra drove in a late consolation goal for Watford.
Derby's last win at Pride Park had come when they
beat Crystal Palace on 24 March
but they ended their wait for another in emphatic style.
Keogh converted from Ward's cross to set manager Nigel Clough's side on their way before Hendrick's far-post header back across goal beat Almunia.
Sammon's stylish finish after a surge towards goal gave him a goal on his home debut and left the visitors shaking their heads.
Watford's predicament only got worse when a Ward effort was tipped on to the post by Almunia to leave highly-rated prospect Hughes a simple finish for his first goal for Derby.
Ward was rewarded for his performance with a goal before Watford denied Derby a clean sheet through Vydra's shot.
Derby County 01 Fielding 02 Brayford 03 Roberts (Buxton - 66' ) 06 Keogh 16 O'Connor 04 Bryson Booked (Doyle - 89' ) 07 Coutts 08 Hendrick 19 Hughes (Jacobs - 83' ) 10 Ward 32 Sammon Substitutes 13 Legzdins 05 Buxton 21 Gjokaj 12 Jacobs 09 Tyson 11 Robinson 14 Doyle Watford 01 Almunia 03 Dickinson 12 Doyley 33 Nosworthy 07 Yeates (Battocchio - 84' ) 08 Hogg Booked 16 Murray (Anya - 64' ) 18 Pudil (Cassetti - 64' ) 22 Abdi 10 Iwelumo 20 Vydra Substitutes 30 Bond 27 Cassetti 31 Hoban 11 Forsyth 21 Anya 28 Battocchio 13 Beleck