Andre-Pierre Gignac kept Marseille's perfect record intact on Saturday as he scored the lone goal in the 84th minute to lead his side to a 1-0 victory at Valenciennes.
Gignac scored in both of Marseille's previous wins, and he was needed once more in the closing stages on Saturday.
Valenciennes was second best for much of the match, but the home side nearly took the lead 10 minutes from time when Loris Nery sent a shot whistling past the post from outside the penalty area.
A few minutes later, Marseille found the breakthrough as Andre Ayew's header was parried by Valenciennes goalkeeper Nicolas Pennetaud, allowing Gignac to tap in the rebound from a few yards.
The hosts had another great chance in the 87th, but Opa Nguette's shot from the middle of the box flashed inches past the left post.
Lyon sustained a 1-0 home defeat against Reims on Saturday to ruin its perfect start to the campaign. Lyon's Clement Grenier failed to convert a penalty kick in the 72nd minute, and Reims snatched the lone goal four minutes later through Odair Fortes.
Rennes claimed a 2-1 win at Evian behind a first-half brace from Nelson Oliveira, Guingamp earned its first win with two goals from Mustapha Yatabare in a 2-0 triumph against Lorient, Montpellier notched a 2-1 win over 10-man Sochaux with a goal from Siaka Tiene deep into stoppage time, while Henri Saivet's 32nd-minute goal was enough to help Bordeaux edge Bastia, 1-0.