Craig Noone came off the bench to rescue a draw for Cardiff City that maintains their five-point lead at the top of the Championship.
Cardiff were heading for a second successive defeat as Derby protected Conor Sammon's second-half opener.
The visitors had dominated up to Sammon's goal, with Chris Martin denied by a marginal offside decision.
But Noone added late impetus and rose at the far post to head home Andrew Taylor's cross eight minutes from time.
After looking so comfortable for the majority of the game, Derby were forced to hang on for a point as Cardiff finally applied some pressure.
Noone, sent off when the sides met at Pride Park in November, was the instigator as he replaced Tommy Smith after 72 minutes.
- Craig Noone was sent off for two yellow card when Cardiff met Derby at Pride Park in November
- Six minutes after his dismissal, Derby equalised to secure a 1-1 draw
- Noone's goal was his first since Boxing Day, taking his tally to six for the season
The substitute almost grabbed a spectacular winner when his curler came within inches of finding the top corner.
Defeat would have been tough on Derby - whose run without a win extends to seven games - as they capitalised on a nervous Cardiff display and enjoyed the better chances.
Paul Coutts fizzed a half-volley that was deflected wide by home goalkeeper David Marshall and the visitors screamed for a penalty when a diving Ben Turner looked to have used his arm to block Jeff Hendrick's drive.
Careless Cardiff passing then allowed Derby to break and the move eventually ended with Chris Martin finding the bottom corner.
His celebration was short-lived, though, as he was flagged for offside. Replays suggested the assistant referee made the wrong call.
After the break, Marshall kept out another low strike from Coutts as the home crowd's frustration grew.
Derby's dominance was rewarded, though, when Sammon slotted home from Ben Davies's cross on 75 minutes. Almost predictably, the chance came after Cardiff lost possession down their own right flank.
A third defeat in four games looked a distinct possibility as Cardiff failed to generate any momentum, but Noone's introduction immediately changed the mood.
The winger is known more for his dribbling skills than his aerial power but he rose purposefully at the far post to meet Taylor's left-wing cross, directing the ball back across goal into the bottom corner.
Cardiff pushed for the winner and Noone's 18-yard curler almost obliged, before another substitute, Rudy Gestede, lashed over from six yards in injury time.
Cardiff City manager Malky Mackay said: "To come back and get the goal showed the resilience in that last 15 minutes, and we nearly got the winner.
"On another day Rudy would have done better a few yards out. But we showed great spirit and endeavour and I suppose a point is a fair result.
"It's another point towards where we would like to go."
Derby County first-team coach Andy Garner said: "With the disallowed goal I had a word with the assistant referee at half-time, which is not the best of times, but I asked him if he was 100% happy with his decision and he said he was.
"I have seen the replay and Chris [Martin] is half a yard onside.
"Chris walked in at half-time and said there was no way he was offside, and he was right. As a striker you know if you are onside or offside."
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Live Text Commentary
Full Time The game is over, as the referee blows his whistle.87:55
Outswinging corner taken left-footed by Peter Whittingham from the left by-line.87:45
Andrew Taylor takes a shot. Valentin Gjokaj gets a block in.85:39
Unfair challenge on Craig Noone by Michael Jacobs results in a free kick. Free kick taken by Peter Whittingham.84:39
Outswinging corner taken right-footed by Ben Davies from the right by-line to the near post, Peter Whittingham manages to make a clearance.84:05
Craig Noone produces a left-footed shot from the edge of the area and misses to the left of the goal.83:01 Substitution
Substitution Rudy Gestede joins the action as a substitute, replacing Craig Conway.82:59
Jake Buxton is penalised for a handball. Peter Whittingham takes the direct free kick.81:20
The assist for the goal came from Andrew Taylor.81:20 Goal scored
Goal! - Craig Noone - Cardiff 1 - 1 Derby Craig Noone scores a headed goal from inside the six-yard box. Cardiff 1-1 Derby.75:55 Substitution
Substitution (Cardiff) makes a substitution, with Joe Mason coming on for Heidar Helguson.74:57
The assist for the goal came from Ben Davies.74:57 Goal scored
Goal! - Conor Sammon - Cardiff 0 - 1 Derby Conor Sammon finds the back of the net with a goal from close in to the bottom left corner of the goal. Cardiff 0-1 Derby.72:16
Peter Whittingham takes a short corner.71:26 Substitution
Substitution Craig Noone is brought on as a substitute for Tommy Smith.70:57 Substitution
Substitution Craig Forsyth goes off and Michael Jacobs comes on.70:03
Craig Conway fouled by Chris Martin, the ref awards a free kick. Peter Whittingham takes the free kick.65:43
Fraizer Campbell produces a right-footed shot from the edge of the area and misses to the left of the target.63:38
Corner taken right-footed by Craig Conway, save made by Adam Legzdins.63:25
Fraizer Campbell takes a shot. Blocked by Jake Buxton.
Peter Whittingham takes a shot. Blocked by Richard Keogh.58:46
Ben Davies crosses the ball in from the free kick.58:46 Booking
Booking Tommy Smith receives a yellow card.58:26
Tommy Smith gives away a free kick for an unfair challenge on Paul Coutts.57:03
Chris Martin concedes a free kick for a foul on Craig Conway. David Marshall takes the direct free kick.55:03
Tommy Smith produces a right-footed shot from just outside the penalty box that goes wide left of the target.53:57
Valentin Gjokaj fouled by Ben Nugent, the ref awards a free kick. Free kick taken by Adam Legzdins.53:34
Corner from the left by-line taken by Craig Conway, save by Adam Legzdins.53:23
Fraizer Campbell takes a shot. Blocked by Jake Buxton.50:19
Peter Whittingham takes the direct free kick.50:19 Booking
Booking Paul Coutts is cautioned.49:50
Free kick awarded for a foul by Paul Coutts on Fraizer Campbell.45:57
Fraizer Campbell is caught offside. Adam Legzdins restarts play with the free kick.45:01
The referee blows his whistle to start the second half.45:00 +3:45 Half time
Half Time The ref blows to signal half-time.45:00 +1:11
Peter Whittingham is adjudged to have handled the ball. The free kick is swung in right-footed by Ben Davies, David Marshall makes a save.44:05
Fraizer Campbell concedes a free kick for a foul on Paul Coutts. Direct free kick taken by Adam Legzdins.42:04
Aron Gunnarsson takes a shot. Jake Buxton gets a block in.40:08
Tommy Smith sends in a cross.38:40
Free kick awarded for an unfair challenge on Craig Forsyth by Heidar Helguson. Adam Legzdins takes the free kick.37:14
Free kick awarded for an unfair challenge on Chris Martin by Ben Turner. Free kick crossed by Paul Coutts.35:24
Foul by Chris Martin on David Marshall, free kick awarded. Direct free kick taken by David Marshall.35:05
Short corner worked by Jeff Hendrick.34:43
Paul Coutts takes a shot. Save by David Marshall.29:18
Chris Martin is ruled offside. David Marshall restarts play with the free kick.25:45
Inswinging corner taken from the left by-line by Jeff Hendrick.23:55
Paul Coutts concedes a free kick for a foul on Tommy Smith. Free kick taken by Peter Whittingham.22:51
Ben Turner takes a shot. Save by Adam Legzdins.20:49
Outswinging corner taken from the right by-line by Jeff Hendrick.20:37
Jeff Hendrick takes a shot. Blocked by Ben Turner.18:56
Paul Coutts takes the free kick.18:56 Booking
Booking Aron Gunnarsson is cautioned by the ref for unsporting behaviour.18:39
Aron Gunnarsson gives away a free kick for an unfair challenge on Jeff Hendrick.16:17
Foul by Conor Sammon on Fraizer Campbell, free kick awarded. David Marshall takes the free kick.16:06
Conor Sammon takes a shot. Blocked by Aron Gunnarsson.12:21
Peter Whittingham crosses the ball from the free kick left-footed from left channel, Jake Buxton manages to make a clearance.12:21 Booking
Booking Valentin Gjokaj is given a yellow card.12:10
Craig Conway fouled by Valentin Gjokaj, the ref awards a free kick.11:15
Richard Keogh fouled by Fraizer Campbell, the ref awards a free kick. Adam Legzdins takes the direct free kick.10:42
Jeff Hendrick takes a shot. Blocked by Aron Gunnarsson.10:14
Ben Turner concedes a free kick for a foul on Chris Martin. Craig Forsyth restarts play with the free kick.9:10
Craig Forsyth produces a left-footed shot from just outside the penalty box that misses to the left of the target.8:46
Free kick awarded for a foul by Heidar Helguson on Ben Davies. Paul Coutts takes the direct free kick.7:23
Ben Davies takes the inswinging corner, clearance made by Craig Conway.7:08
Ben Davies takes a shot. David Marshall makes a save.5:59
Free kick awarded for a foul by Heidar Helguson on Jake Buxton. Direct free kick taken by Paul Coutts.4:46
Tommy Smith delivers the ball.3:46
Outswinging corner taken right-footed by Ben Davies, Fraizer Campbell makes a clearance.2:49
Corner taken by Craig Conway from the left by-line, Header from deep inside the penalty area by Ben Turner goes harmlessly over the crossbar.2:02
Unfair challenge on Craig Conway by Ben Davies results in a free kick. Shot comes in from Craig Conway from the free kick, Chris Martin gets a block in.1:22
Chris Martin produces a left-footed shot from just outside the penalty box that misses to the left of the target.0:18
Free kick awarded for an unfair challenge on Craig Conway by Jeff Hendrick. Free kick taken by Andrew Taylor.0:00
The referee gets the match started.
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