Mike Edwards was County's first hero, forcing in a Lewis McMahon corner eight minutes from time to level at 2-2 as the Stags' problems at dealing with high crosses again cost them points.
Then four minutes from time in-form Glynn Hurst was the second County hero to complete a remarkable fightback, prodding in his fourth goal in three days after substitute Andy White caused mayhem in the home penalty area.
The double strike came just when substitute Gareth Jelleyman's second ever career goal, six days after his first, looked to have won the derby for the Stags.
That goal was a disaster for former Mansfield keeper Kevin Pilkington who failed to collect a cross, allowing Richie Barker's flick-on at the near post to be touched in by Jelleyman on the hour.
County had lost influential midfielders David Pipe and Matt Gill to injury just before kick-off.
Mansfield player-manager Carlton Palmer too made five changes as he sought a winning formula for only the second time this season.
Three of those new faces came into the Stags' back four and one of them, Alex Baptiste, almost let in Steve Scoffham in the first minute but the young centre-back recovered well from an initial slip.
After a frenetic opening seven minutes Fraser McLachlan drove narrowly over when the visitors failed to clear a Simon Brown cross.
But in the 15th minute there was no let off for the league leaders when Barker fired the home side in front, shooting on the turn into the bottom corner from eight yards after a flick-on by Chris Beardsley.
Roared on by 1,700 travelling fans, County levelled just three minutes later. Baptiste made a mess of clearing Julien Baudet's free-kick into the defensive wall and Scoffham passed for Hurst to equalise.
Midway through the first half McMahon had long appeals for a penalty waved away as County pressed to complete their fightback.
Then, with County now on top, veteran keeper Kevin Pressman denied both Scoffham and Hurst with fine reaction saves.
Substitute Jelleyman, Barker and Brown all went close to restoring Mansfield's lead at the start of the second period.