Marseille had to settle for a point in a 1-1 draw at home to Ligue 1 strugglers Dijon on Saturday.
Rudy Garcia's hosts predictably made all the running at the Stade Velodrome, but went behind in first-half injury time when Gregory Sertic put the ball into his own net.
Dimitri Payet pulled them level only three minutes into the second half, but that was as good as it got for Marseille.
Even a victory could not have improved their fifth position in the league. But after a disappointing result against opponents who were taking their sequence without victory to six matches, Marseille are three points adrift of Lyon, who have played two games fewer.
Dijon's determined display takes them four points clear of bottom-of-the-table Lorient.
Out-of-sorts Bastia remain above Lorient only on goal difference after extending their long run without victory in a 1-0 home defeat against mid-table Lille.
Nicolas de Preville scored the only goal of the match early in the second half in Corsica.
Lille's interim manager Franck Passi therefore banked the points, while Bastia are left to contemplate a 13th league fixture without a win since early December.