Super-sub Leon Best rescued a point for 10-man Derby in a fierce showdown with arch-rivals Nottingham Forest as the game at the City Ground ended in a 1-1 stalemate.
Britt Assombalonga's excellent 72nd-minute strike looked to have put Stuart Pearce's men on course for another maximum haul, but Best was the Rams' hero with an equaliser eight minutes from time.
Derby defender Jake Buxton received his marching orders late on but Forest could not make their advantage count in the remaining minutes as the spoils were shared.
Forest named an unchanged side from the one that won at Sheffield Wednesday, while Derby brought in Ryan Shotton for his Rams league debut, as well as Will Hughes and Simon Dawkins.
Derby midfielder John Eustace was the man first in the book after six minutes for a crude challenge on Forest skipper Chris Cohen, before Chris Burke was penalised for a foul on Hughes just outside the Reds box, with Johnny Russell curling his free-kick wide.
The whole of the City Ground were on their feet after 10 minutes, both home and away fans applauding in unison as they marked the 10th anniversary of the death of Brian Clough, who famously managed both these sides with great success.
The Reds suffered a blow a quarter of an hour in as an emotional Cohen, who has been plagued with injury problems, hobbled off with Robert Tesche coming on for only his second Forest outing.
Another Andy Reid free-kick came to nothing, before Richard Keogh did well to beat Assombalonga in the air as the Forest striker rose to meet Burke's cross in what had been a hectic opening 25 minutes.
The game settled down as Derby began to gain a foothold in midfield, with Hughes and Craig Bryson harrying and probing before Forest were forced into a second substitution just prior to the break. Reid had been struggling since an accidental coming together with Assombalonga, and he came off to be replaced by Ben Osborn.
That unscheduled move seemed to re-galvanise Forest, who saw Assombalonga head Henri Lansbury's free-kick over Lee Grant's bar, while Tesche fizzed a 25-yarder narrowly wide and Lansbury blasted off target as Forest ended the first half in the ascendancy.
Michail Antonio tested the palms of Grant after cutting inside Shotton and letting fly from 20 yards in a second half that was failing to match the intensity of the first 45 minutes, before the incursion of three pitch invaders stoked up the atmosphere amongst the crowd of 30,000.
The delay in proceedings clearly helped Forest and they duly took the lead in the 73rd minute as Antonio set up Assombalonga, who spun on a sixpence and cracked a fierce shot into the bottom corner from 12 yards.
Antonio then headed Jack Hunt's cross narrowly wide and with the Reds on top, Derby boss Steve McClaren, who had already replaced Russell with Best, sent on Jordan Ibe and Ivan Calero in a bid to get the Rams back on level terms.
Karl Darlow raced off his line to deny Best, but in the 80th minute, the Rams equalised. Keogh headed a Bryson free-kick against the bar and the ball bounced down to Shotton, whose effort looked like it might have crept over the line despite the best efforts of Darlow, before Best made sure.
Three minutes from time, Buxton saw red for bringing down Burke after referee Paul Tierney had already blown for a Forest free-kick.
In the last of eight minutes of added-on time, Tesche had a header saved by Grant as the honours were shared.