BURY opened up a seven-point gap between themselves and the League Two drop zone with a smash and grab win at the Cherry Red Records Stadium.
Danny Mayor broke the Wimbledon hearts, storming through in the 94th minute before coolly slotting past onrushing goalkeeper Ross Worner.
It was a crushing blow for the hosts who had dominated 80 minutes before the visitors burst into life.
Former Shaker Danny Hylton was a thorn in their side all afternoon, forcing Brian Jensen into a string of important saves.
But Bury came into their own following the introduction of substitute strikers Clive Platt and Jean-Louis Akpa Akpro, who combined to create three match-winning chances.
They all fell to Akpa Akpro, who blasted over from 10 yards then hit the crossbar before over running his third chance, which was gathered by Worner.
A point would have been a fair result on the balance of play.
But Mayor’s fantastic late run and strike gave Bury the maximum reward for a second successive clean sheet away from home, following their 0-0 draw at Accrington on Tuesday night.
The Shakers may have only moved up one place to 20th in the table, but their seven-point cushion over second-bottom Torquay United will ease the relegation pressure.