Chesterfield suffered late, cruel heartache as they handed three points to another side in the relegation battle.
Town contrived to lose their must-win game against Bury 2-1, having led 1-0 until the 80th minute.
Tom Anderson was red carded in the final 11 minutes and although debutant keeper Thorsten Stuckmann produced a fantastic penalty save, he was then beaten by a wonderstrike before his blunder gifted Bury a winner.
The result leaves the Spireites second from bottom on 27 points, seven points from safety with 14 games remaining.
At full-time the home supporters left in the ground were heard to boo in frustration, but at half-time it was all going so well.
Sylvan Ebanks-Blake, handed his first league start of the season, had impressed early on before setting up Kristian Dennis to score the opener.
But Town simply let the game get away from them after the interval, a lack of composure in possession eventually inviting disaster.
Osman Kakay, who had a poor game on the right, set Bury away on the game’s first break and Ian Evatt did just enough to ease Tom Pope away from the dangerous cross.
From Chesterfield’s perspective it was all a bit rushed in the early stages, more care needing to be taken in possession.
One nice bit of football, involving all three strikers, ended in a Dan Jones cross that Liam Grimshaw flicked on and a defender had to nod over the bar.
With 15 minutes gone the Spireites began to build up a head of steam, Kakay’s cross dropping to Ebanks-Blake 18 yards out, but he opted for a touch instead of a shot and miscontrolled badly allowing Bury to clear.
Ebanks-Blake was pounding the turf in frustration after the best chance of the opening stages went begging, the striker taking down a ball over the top with a sublime touch and seeing his low shot deflected past the post.
Having been involved in two of Town’s best moments, it was perhaps no surprise that Ebanks-Blake played a big part in the opening goal.
His control allowed him to nick the ball away from his marker and then he lofted it over the top for Dennis to run in on goal, before bobbling a finish past Joe Murphy and into the net.
Chesterfield were saved by woeful finishing by Ryan Lowe as the half neared its conclusion, the Bury striker somehow being left all alone to take a through ball, sweeping it wide despite having acres of space and plenty of time.
And the Shakers continued to press before the break, Anderson’s wayward touch allowing Scott Burgess to stride forward and fire over from distance, albeit with the aid of a deflection.
Lee Clark’s men fashioned an opportunity the other side of the interval too, a driven cross headed back into the middle by Greg Leigh, Ryan Lowe unable to keep his headed effort down.
Anderson made two important interventions to deny the strangely quiet Pope, before having to go off and get repairs to a facial injury and returning with his almost customary head bandage.
Kakay’s lack of control cost him a yellow card on the hour mark, a poor touch gifting Leigh the ball before the Spireites right-back clattered the Shaker.
The game was becoming entrenched in the Chesterfield half, the hosts unable to wrestle control of possession from Bury, Gary Caldwell reacting by replacing Dan Gardner and Kristian Dennis with Reece Brown and Reece Mitchell.
Bury kept coming however and the Proact breathed a sigh of relief when Lowe’s close range header came back off the woodwork, Evatt making a desperate clearance to stop George Miller from reaching the rebound.
Rai Simons was the third replacement for the home side, taking the place of Ebanks-Blake who received a deserved ovation for his contribution.
The substitution almost paid immediate dividends, Simons streaking away down the left and passing the ball into the box where Grimshaw arrived unmarked and only had to hit the target but skied his shot.