Bastia claimed a surprise 2-0 victory over Nantes thanks to goals from Giovanni Sio and Floyd Ayite at the Stade de la Beaujoire.
Nantes were on top for much of the first half, but a lack of cutting edge in the final third from Ligue 1's joint-second lowest goalscorers halted their progress.
The clearest chance of the opening 45 minutes fell to Bastia, and debutant Sio capitalised by bringing down a lobbed ball forward before chipping his effort over a helpless Remy Riou.
Nantes continued to dictate the tempo either side of the half-time interval, but the Bastia defence held firm to frustrate Michel Der Zakarian's side.
The home side's chances were dealt a blow in the 65th minute when Fernando Aristeguieta was shown a straight red card for catching Sebastien Squillaci with his studs.
Bastia capitalised on their numerical advantage to wrap up the win through Floyd Ayite, who led the counter-attack before sending a swerving effort through Riou to secure his side the points.