It was a tough, gritty struggle of a game at times but the Robins came up with sufficient inspiration at key moments to ensure that their season will be extended past next week's final league game.
Notts County, meanwhile, face a nervous final game of the season at home to Bury next week in order to ensure Football League survival.
Cheltenham took control in the third minute when striker Steve Guinan ran onto a long ball from Jerry Gill and smashed a first time shot that sailed past goalkeeper Kevin Pilkington.
The goal settled any nerves among the home side and they went on to create further chances with Grant McCann sending a free-kick inches wide and Guinan seeing a fierce volley held by Pilkington.
Notts County suffered a further setback in the 28th minute when midfielder Lee Crooks was carried off injured. He was replaced by Daniel Chillingworth with County abandoning their starting formation and switching to three at the front.
David Pipe shot over the bar and Steve Scoffham went close with a header for County but Cheltenham captain John Finnigan shaved the crossbar with a shot from the edge of the box as the home side remained in the driving seat in the lead up to half-time.
County began the second half strongly but were unable to fashion many clear chances at goal, Cheltenham goalkeeper Shane Higgs saving the best chance from midfielder Chris Palmer.
At the other end, Cheltenham were able to exploit the gaps as County pushed forward with Pilkington having to save well from Guinan and substitute Ashley Vincent.
Pilkington then pulled off a double save from Damian Spencer and David Bird but the match was decided eight minutes from time. Vincent raced onto a through ball from Finnigan before planting a shot beyond Pilkington to send the home fans home happy.