Lyon's chances of winning Ligue 1 this season have taken a blow with a 4-1 away defeat to Bastia.
The home side broke the deadlock on the stroke of half time through Florian Thauvin, who shot home after being released by Wahbi Khazri.
Lisandro Lopez restored parity for Lyon nine minutes into the second half when he turned in Yoann Gourcuff's delivery.
However, two minutes later Anthony Modeste restored Bastia's advantage, latching onto Khazri's through-ball to find the target from close range.
Thauvin secured the points for the home side just after the hour mark when assisted by Claudio Beauvue, he fired in from the centre of the Lyon penalty area.
Khazri added the icing on the cake for Bastia when he scored their fourth goal of the evening three minutes from full time.