Saint-Etienne moved into fourth place in Ligue 1 after a 2-1 win over Valenciennes on Saturday.
Saint-Etienne began the match with a fast tempo, something which the home side found difficult to live with, and they were reduced to ten men after just four minutes.
Carlos Sanchez was dismissed from play for a dangerous challenge on Fabien Lemoine, to hand the away side an immediate advantage.
Pierre-Emerick Aubameyang came close for the away side after nine minutes, but his effort was pushed to safety by Nicolas Penneteau.
Saint-Etienne again came close after 22 minutes via Jonathan Brison, but his effort was just wide of the target.
The home side were not without their chances, however, and Remi Gomis came close after 26 minutes before controversy emerged once more.
Saint-Etienne were also reduced to ten men after 33 minutes when Jean-Pascal Mignoet was shown a red card for a challenge on Foued Kadir, although the decision looked harsh.
Vincent Aboubakar came close for the home side after 37 minutes, but his effort was pushed to safety before Ruby Mater brought the best out of Stephane Ruffier.
Valenciennes took the lead after 69 minutes when Aboubakar found a cool finish inside the area after good work from Kadir.
The home side's lead did not last long, however, as Aubameyang's right-footed shot found the bottom corner.
The equaliser sparked Saint-Etienne into life and they found a winner after 77 minutes when Bakary Sako found the bottom corner with a powerful finish.
Valenciennes missed a golden chance to level the match after 79 minutes, but Gregory Pujol struck the post from close range.
Saint-Etienne held on, however, to secure a vital victory in their fight for Champions League qualification.
