The French international scored the only goal of the game at the Stade Velodrome to help Les Phoceens close the gap on leaders Paris Saint-Germain to four points.
"It was solid once again," the club's official website quotes Gignac as saying. "It would be nice to be able to drive a nail in winning by two clear goals.
"This is a great celebration for the new platform."
Les Parisiens can stretch their lead back to seven points with victory over Rennes on Saturday.