Sadio Diallo's first-half goal has given Bastia victory and denied Caen the chance to move into second in Ligue 1.
The Normandy outfit had to withstand early pressure as Gael Danic brought a save out of keeper Remi Vercoutre.
However, Caen also came close to taking the lead at the Stade Armand-Cesari-Furiani when Andy Delort's fizzing shot forced a flying stop from Jean-Louis Leca.
Instead, it was the Corsicans who edged in front just after the half-hour mark when Diallo's free kick found the top corner of the net.
The Guinean international almost doubled the home side's advantage before half time when he nodded Danic's cross goalwards, only to be denied by Vercoutre.
Diallo then turned provider by teeing up Danic, whose shot was saved before Sebastien Squillaci headed over from close range.
Caen tried to snatch a point late on, but Delort's effort was saved as Bastia held on for victory.
