Strike pairing Deane Smalley and Paul Heffernan bagged a second-half goal apiece as the Latics shrugged off their dismal run with a comfortable victory.
Exeter could have taken an early lead when midfield man Bertie Cozic clipped the bar from fully 30 yards. Adam Stansfield was denied by home keeper Darryl Flahavan but Oldham took charge and Danny Whitaker went close on three occasions.
The breakthrough came on 51 minutes as Dean Furman found Smalley who produced a crisp 12-yard finish inside the far post.
And Oldham, who went into the game as the division’s lowest scorers, made it two goals in seven minutes when Heffernan’s deflected shot looped over keeper Andy Marriott.
The on-loan Doncaster man then teed up Whitaker for a drive which flew off target. Exeter had a good chance to pull one back just after the hour but Stansfield blazed wide from 14 yards, meaning the Grecians have now suffered three straight defeats without scoring.