Olivier Giroud snatched all three points for title-chasing Montpellier HSC as they struggled to overcome a resilient Saint-Etienne.
Souleymane Camara tested Les Verts goalkeeper Stephane Ruffier on the half-hour mark after linking up with the in-form Giroud.
Camara then thought he had opened the scoring two minutes after the interval, only for it to be ruled out for offside.
Jeremy Clement then denied the Senegalese striker once again by clearing off the line.
Jean-Pascal Mignot saw red 14 minutes from time for a foul on Remy Cabella.
With the game heading for a draw, it was left to Ligue 1's top scorer to decide matters with just one minute remaining.
Giroud struck a fierce shot low into the left-hand corner to send La Pallaide to the top of the table.
