Giroud proved to be the match-winner again, grabbing his 18th goal of the season in the 89th minute as la Paillade secured a late victory over their 10-man opponents
With much of the game uninspiring and few chances created, the tables turned after 77 minutes when Jean Pascal Mignot saw red over a tackle on Remy Cabella. A minute before time however, Olivier Giroud grabbed his 18th league goal of the season to propel Montpellier to the top of the table.
After an early period of sparring between the two sides, it would be the visitors who would fashion the first chance on goal as Pierre Emerick Aubameyang fired high and wide after good work from Sinama-Pongolle.
Moments later, the host also created a chance of their own, which narrowly went wide of Stephane Ruffier's goal. Giroud fed through Souleymane Camara, who went close from 15 yards out as they sought a continuous attacking rhythm.
It would prove to be a lacklustre first half on the whole, as attacking chances came at a premium. Camara took advantage of a minor blunder to tee up Giroud, who would be denied by Ruffier.
Rene Girard's men stepped up the tempo, but once again failed to negotiate a way past a sturdy les Verts defence. Henri Bedimo whipped in an in-swinging corner, though Giroud's header failed to result in a goal as the sides entered the interval level at 0-0.
The second half fared no better, as both teams cancelled each other out in a rather meek game, with play situated mainly in midfield. Aubameyang's headed pass in towards Sinama Pongolle went close, dragging his effort wide.
Montpellier rarely threatened, although Giroud, who has 17 goals this season, scuppered two chances in search of that elusive opener. First, his tame shot was comfortably handled by Ruffier and minutes later, he only went close with a header.
Christophe Galtier's men were subsequently dealt a blow as the game neared its end. Jean-Pascal Mignot lunged in on Remy Cabella, and referee Fredy Fautrel had no hesistation in sending off the defender.
La Paillade had efforts late on to snatch a victory through Marco Estrada and Cabella, and they finally broke the deadlock one minute from time. The numerical advantage told as Giroud fired in a volley into the bottom corner and steal all three points.
Following the victory, Montpellier go top of Ligue 1, one point ahead of PSG who face Bordeaux Sunday evening. Rene Girard's men take on Sochaux next, as Saint Etienne host Nice.