Toulouse failed to move level on points with Ligue 1 leaders Paris St Germain and Marseille for the second successive week after a Chahir Belghazouani double inspired Ajaccio to a surprise 4-2 victory.
Having slipped up at Bordeaux last weekend, coach Alain Casanova this week demanded a response from his side but it failed to materialize as they slumped to their third defeat of the season.
Despite being boosted by a fourth-minute own goal from Anthony Lippini, Toulouse trailed at half-time after goals from Frederic Sammaritano and Belghazouani.
Sigamary Diarra made it 3-1 before Aymen Abdennour gave Toulouse brief hope which was extinguished by Belghazouani's second of the night.
Hosts St Etienne upheld the form book with a regulation 2-0 win over Troyes at Stade Geoffroy-Guichard.
The result was enough to take the home side to third in the table, while their defeated opponents are languishing in second-bottom place with just seven points.
Troyes managed to hold the stalemate during the first half but conceded two minutes into the second period through Renaud Cohade, before Pierre-Emerick Aubameyang eased late nerves with an 88th-minute finish.
Two goals in three second-half minutes from Foued Kadir and Mathieu Dossevi helped Valenciennes come from a goal down to beat Bastia and move up to fourth.
The visitors survived an early onslaught from Bastia to take the lead through Kadir just after the half-hour mark, but Anthony Modeste drew them level from the penalty spot in the 39th minute.
Julian Palmieri then put the hosts ahead in the 61st minute but Kadir leveled for Valenciennes after 77 minutes before he teed up Dossevi to complete the comeback.
Evian leapt out of the relegation places as they inflicted a first home defeat on Reims since the opening day of the season.
Kevin Berigaud and Youssef Adnane scored in either half to fire the visitors, who had lost their past three league games, 2-0 ahead.
A Cedric Cambon own goal with 18 minutes left meant they had to sweat on the victory but they held on to move ahead of Sochaux, who host Lyon on Sunday.
Salomon Kalou scored the only goal of the game as Lille put their midweek humbling behind them with a 1-0 victory over visiting Brest.
Rudi Garcia's side were on the wrong end of a 6-1 hammering by Bayern Munich in the Champions League but successfully recorded their third straight league win.
Kalou produced the decisive moment, slotting home on the stroke of half-time.
On Friday night, Rennes were grateful to goalkeeper Benoit Costil after he saved a late penalty minutes before Jonathan Pitroipa wrapped up a 3-1 victory at Nancy with a goal five minutes from time.
Rennes took the lead when Mevlut Erding, who had lost his marker, headed beyond goalkeeper Guy N'dy Assembe.
Nancy equalized six minutes into the second half. Simon Zenke turned Jean-Armel Kana-Biyik inside out before slamming a right-footed shot into the top left corner of the goal.
The visitors struck again through Alessandrini after 74 minutes before Costil saved Paul Alo'o Efoulou's spot kick and Pitroipa sealed the victory.
