LOSC keeper Vincent Enyeama produced a sensational performance in goal for the hosts as he kept out Radamel Falcao and his teammates time and again, with a double from Nolan Roux proving enough to secure the points for Rene Girard's men.
The result sees Rene Girard's men leapfrog their opponent in the table and sees them stake a claim as genuine contenders in the French title race.
Nolan Roux put the hosts in front midway through the first half when he kneed home from Marko Basa's knock-down after the central defender connected with Florent Belmont's corner.
Claudio Ranieri's side dominated for large chunks of proceedings but couldn't find a way past an inspired Enyeama in les Dogues' goal. Lille hit its opponent on the counter in the second period as Salomon Kalou and Rio Mavuba combined to set up Roux for his second to seal the victory.
The principality outfit continued to search for a way back into the game but an incredible late double stop from Enyeama to deny Radamel Falcao and Emmanuel Riviere typified the visitors' luck as they were condemned to their first league defeat of the season.