Michael Hector's first Cheltenham goal denied Gillingham the chance to clinch the npower League Two title.
The centre-half, on loan from Reading, headed home Billy Jones' corner as the Robins maintained their own automatic promotion challenge with a 1-0 win.
Second-placed Port Vale were also forced to put the champagne on ice after Rochdale's Jason Kennedy glanced home a stoppage-time equaliser in a 2-2 draw.
Rochdale went in front when Liam Chilvers headed into his own net, but top scorer Tom Pope nodded Vale level moments later.
Chilvers made amends for his earlier error but Kennedy had the last word.
Matt Paterson's injury-time strike earned Burton a 1-0 win against Plymouth and kept them in the automatic promotion places.
Rotherham moved to within a point of the automatic promotion places with a 2-1 win against Fleetwood Town, secured with goals from Daniel Nardiello and Kieran Agard either side of a strike from David Ball.
Northampton were beaten 2-0 by York, who kept their survival hopes alive with a strike from Ashley Chambers and John Johnson's own goal.
Chesterfield snatched a 2-2 draw with Bradford with Sam Togwell's injury-time equaliser.
Bradford twice took the lead, through Nahki Wells and Ricky Ravenhill, but Tendayi Darikwa equalised once and Togwell had the final say.
At the bottom, Aldershot went down 2-1 to Wycombe who took the lead through Matt McClure and Joel Grant got the winner after Craig Stanley's equaliser.
Elsewhere, AFC Wimbledon drew 2-2 with Exeter, Oxford United beat Dagenham and Redbridge 1-0, and Southend drew 0-0 with Bristol Rovers.