A thrilling late fightback took Burnley back into the top six as Tyrone Mears and Jack Cork both struck in a dramatic final ten minutes to give the Clarets a morale-boosting seventh home win of the season.
Derby looked as though they were going to pull off a painful Ram-raid as they grimly hung on to a lead given to them by Luke Moore's deflected 19th minute shot.
But after piling on the pressure in the second half, Burnley deservedly levelled when former Derby full-back Mears chose the perfect moment to score his first goal for the club.
Mears curled in a perfectly executed free-kick with seven minutes to go as he capped an outstanding individual performance and ended an 18-month wait to open his account in a claret and blue shirt.
And then as Brian Laws' men pushed forward in search of a winner, Cork duly delivered in the 90th minute with a magnificent glancing header.
His second goal of the season sent the temperature at a freezing Turf Moor soaring as the Clarets' never-say-die spirit got their promotion push back on course.
Results earlier in the day had opened the door for the Clarets to return to the play-off places and Laws made three changes to his side in a bid to start another winning run.
Match-winner Jack Cork gets the better of Robbie Savage
Chris Eagles missed out through a back injury with Ross Wallace getting his first league start since mid-September, while Andre Bikey also ended a lengthy absence as he returned as Clarke Carlisle's central defensive partner.
Marney came into midfield in place of Graham Alexander and the Clarets gave themselves the chance of the perfect start when Wallace delivered a trademark left-wing cross which Chris Iwelumo headed wide of the near post.
Bikey then directed a header at goalkeeper Frank Fielding from a Marney corner after Wallace had again popped up with a dangerous ball in.
But Burnley then found themselves on the back foot when out of nothing Derby pounced to take the lead.
Luke Moore puts the Rams ahead
A mis-directed header from Jay Rodriguez surrendered possession in the Rams' half and within seconds they had worked the ball forward to Moore.
The on-loan West Brom striker still had plenty to do but after cutting in onto his right foot he let fly from 22 yards and with the aid of a deflection off Carlisle found the top corner.
The goal was a hammer blow to the Clarets and manna from heaven for Derby who then just sat back and invited Burnley to try and play through them.
And frustratingly for the Clarets they couldn't find an answer to the puzzle before the end of a disappointing first half.
Lacking width on the right until Wade Elliott drifted out to support Mears, whose marauding runs had provided some of the few bright spots for the home side, the Clarets were too one dimensional and reduced largely to wayward long-range efforts.
Rodriguez did his best to find a way through the packed Rams' rearguard and at least stretched the Derby back line but his shot from an angled Marney pass after half an hour was the only time Fielding was tested before the break.
Jay Rodriguez tries to lead a fightback
With the ever-willing Rodriguez moving into a more central position alongside Iwelumo and Elliott positioned on the right flank, the Clarets looked to carry the fight to the Rams at the start of the second half and early flurry of crosses suggested at better to come.
Still clear-cut chances remained elusive, although Iwelumo went close to turning in a deflected ball in from Wallace and Rodriguez shot at Fielding on the turn with an hour gone.
However, the momentum was building and Iwelumo had a chance to level moments later but headed a deep cross from Rodriguez onto the roof of the net with his last touch before making way for Steven Thompson as Laws made his first change.
The Clarets were looking more potent and after a Cork-inspired break just failed to unhinge the County defence, Wallace cracked a shot against the bar when the ball dropped invitingly 25 yards from goal.
With Derby happy to sit on their lead it was largely one-way traffic and in an effort to find a way through the massed ranks of yellow shirts, Laws sent on new loan signing John Guidetti with just under 20 minutes to go.
Dean Marney earns the crucial free-kick.......
The Clarets were desperate to find a goal from anywhere and finally from the most unlikely source they found it with seven minutes to go.
When Marney went down just outside the penalty area under a challenge from Dean Moxey, Mears and Wallace stationed themselves over the free-kick.
Past history suggested that Wallace might have been the man for the job but Mears accepted the responsibility and from 22 yards curled the ball superbly over the wall and into the top corner to claim only the eighth goal of his career.
The Clarets suddenly sensed they could win it and after Cork had seen one header well saved by Fielding, the England under-21 international tried his luck again and this time magnificently grabbed the clincher.
And Tyrone Mears curls it in to make it 1-1
This time the cross came from Elliott on the right after another patient build-up and a fantastic run beyond the near post saw Cork find the space to flick the ball back past Fielding and into the far corner.
The goal crowned a magnificent comeback by the Clarets and with Lee Grant forced into his only save of the match in injury-time save from a James Bailey shot, one that stunned a Derby side that now has Burnley breathing down their necks in the promotion race.
Burnley: Grant, Mears, Easton, Carlisle, Bikey, Marney (Alexander 81), Cork, Elliott, Iwelumo (Thompson 63), Rodriguez (Guidetti 73), Wallace. Subs: Duff, Edgar, Harvey, Jensen.
Booked: Thompson 75.
Derby: Fielding, Brayford, Green, Barker, Savage, Pearson (Leacock 54), Bailey, Cywka, Moxey, Bueno (Pringle 14), Moore (Porter 82). Subs: Kuqi, Hendrick, Bywater.
Booked: Green 43.
Referee: Mark Haywood