Saloman Kalou hit a 92nd-minute winner as Lille moved six points clear in the Champions League qualification places with a 1-0 home win over Guingamp.
Rene Girard's men peppered the opposition goal throughout the opening half without finding a breakthrough, with Simon Kjaer and Florent Balmont among those going close for the hosts.
The second half proved a similar story for the former Ligue 1 winners as Ryan Mendes was guilty of missing the best chance just after the hour mark.
However, the former Chelsea striker pounced in the closing stages to snatch the win for Lille and propel Les Dogues six points clear of Saint Etienne in the race for Champions League qualification.
