Romain Hamouma's second-half strike proved the difference as St. Etienne went to the top of Ligue 1 with a narrow victory over fellow high-flyers Valenciennes.
Both sides had the chance to move to the top of the standings, level on points with Lyon, with a win Friday night, but it was the hosts who prevailed as they extended their unbeaten run to nine matches.
They dominated throughout at the Stade Geoffroy-Guichard and deservedly sealed all three points when Hamouma netted after Valenciennes had failed to clear their lines in the 73rd minute.
The two teams have been the surprise challengers this season, though St. Etienne midfielder Renaud Cohade was not willing to rest on his laurels against a team that had lost just once in its past seven matches before Friday.
But any hopes of a clash to savor were dashed in a first half of relatively few clear-cut chances.
Pierre-Emerick Aubameyang volleyed wide of the target from just outside the area, while at the other end Valenciennes midfielder Mathieu Dossevi evaded the challenges of several home defenders and burst into the area, though he lost his footing at a crucial point and could only direct a tame shot at Stephane Ruffier.
St. Etienne, perhaps sensing an opportunity at home, upped the ante in the second half, with Aubameyang once again thumping over before forcing Penneteau to make two fine saves.
But there was nothing the Valenciennes keeper could do when Hamouma netted following a goalmouth scramble 17 minutes before the end, with the midfielder firing home after a flick-on from Cohade.
St. Etienne managed to hang on to its lead to ensure it tops the table for the next 24 hours at least.