A dramatic late winner from substitute Jon Daly eased Stockport's relegation worries.
The Republic of Ireland Under-21 international gave Stockport's survival hopes a massive lift with his headed goal seven minutes from time.
It enabled the Hatters to move out of the bottom four as they recorded only their second league victory in 13 games.
Chesterfield, with only two points from a possible 30, suddenly find themselves sliding ever closer to the relegation places following their latest set back.
Yet the night began well for the Spireites who made a dream start taking a sixth minute lead.
David Reeves found the net with an audacious lob from 35 yards as he spotted Swedish goalkeeper Ola Tidman off his goalline.
Stockport needed a piece of inspiration to get back into the game and Chesterfield old boy Luke Beckett provided that shortly before half-time with a fabulous equaliser.
Beckett cut in from the left byline, past two Chesterfield defenders and slotted home his 25th goal of the season from the tightest of angles.
There was little to separate the struggling sides in a second period of few chances and it looked as though both teams would have to settle for a point a piece, which would have done little to ease their plight towards the foot of the table.
But with time running out Daly, who had replaced striker Aaron Wilbraham, came up with the match winning goal.
Rickie Lambert swung over a free-kick from the left which was met by Daly whose header eluded goalkeeper Ben Williams who could only help it into the net.
As Chesterfield pressed forward for a last gasp equaliser, Stockport might have increased their lead on the counter as Beckett squandered two gilt-edged chances.
First he glanced a header narrowly wide from in front of goal and then deep into stoppage time he fired inches wide after bursting through on goal.
