Ten-man Nottingham Forest suffered derby day misery at The City Ground.
Craig Bryson scored the only goal of the game to earn Derby County local bragging rights, as well as The Brian Clough Trophy.
Bryson broke Forest’s hearts with a 55th minute strike, nine minutes after Dexter Blackstock had been red carded by referee Robert Madley.
The striker was given his marching orders after being adjudged to have caught Richard Keogh with an elbow in an aerial challenge.
And Forest were left with a mountain to climb when Bryson made his crucial contribution to send the 4,389 travelling supporters into ecstasy.
Sean O’Driscoll made two changes to the side beaten by Leeds eight days earlier, drafting in Chris Cohen and Lewis McGugan at the expense of Guy Moussi and James Coppinger.
It represented Cohen’s first league start after recovering from the serious knee ligament injury he had suffered in the corresponding fixture last season.
The game started in typically frenzied fashion and Forest had appeals for a penalty waved after seven minutes after a Cox cross from the right hand side appeared to strike the hand of Keogh.
Cohen tested Frank Fielding with a shot from distance but the Derby goalkeeper made a comfortable save.
Andy Reid went in the referee’s book midway through a typically frenzied first half and he was followed soon afterwards by Jake Buxton as temperatures rose.
An in-swinging free-kick from Reid threatened to catch out Fielding, while Gareth Roberts collected a yellow card for a clumsy challenge on Cohen and Fielding was forced to claw away the resultant free-kick from Reid.
Reds skipper Danny Collins headed against the Derby bar from another Halford long throw in the dying seconds of the first half but the whistle had already sounded for an infringement.
Conor Sammon fired over Lee Camp’s bar from distance, while Cox was just inches away from opening the scoring with a spectacular long-range strike on the stroke of half-time.
The second half was less than 60 seconds old when Blackstock was given his marching orders – a decision that mystified not only the striker but also the vast majority of the crowd of 28,707.
And things went from bad to worse for The Reds nine minutes later as Derby took the lead. John Brayford got forward down the right and when he fired in a low cross Bryson was hand to fire in from close range.
Forest made a double change with 15 minutes remaining as they looked to alter the course of the game, introducing Billy Sharp and Henri Lansbury to the action at the expense of Reid and McGugan respectively.
A mistake by Fielding almost presented Forest with an equaliser as he failed to hold a free-kick from Cohen that bounced awkwardly in front of him at the first attempt.
But the Derby ‘keeper was at his best to keep out a rasping shot from Simon Gillett in the dying minutes of the game, diving full length to his left to deny the diminutive midfielder as O’Driscoll’s men strived for an equaliser.
It proved, however, to be an afternoon of intense frustration for The Reds as they were beaten by their fiercest rivals on Trentside for the second successive season.
Camp; Halford (Moloney 78'), Ayala, Collins(c), Harding; Gillett, Cohen, McGugan (Lansbury 75'), Reid (Sharp 75'); Blackstock, Cox
Subs not used: Evtimov (GK), Moussi, Coppinger, Majewski
Booking: Reid 21', Gillett 69', Cox 90', Lansbury 90'
Sent off: Blackstock 46'
Derby: Fielding, Brayford, Roberts (O'Connor 79'), Bryson, Buxton, Keogh (c), Coutts, Hendrick, Hughes, Sammon (Robinson 82'), Ward (Jacobs 66')
Subs not used: Legzdins (GK), Tyson, Gjokaj, Freeman
Scorer: Bryson 55'
Booking: Buxton 23', Roberts 38'
Referee: Robert Madley
Attendance: 28,707 (Away: 4,389)