RC Lens's Champions League hopes suffered another knock when they were held to a 1-1 home draw in the northern derby in Ligue 1 on Saturday.
Although the result lifted Lens to third in the standings on 51 points from 26 games, Franck Haise's team have now only won one of their last seven league matches and have Monaco and Stade Rennais, who have a game in hand, within five points behind them.
The home team had the upper hand in the first half and went ahead thanks a Jose Fonte own goal, but Jonathan David equalised after the break before Brice Samba made numerous spectacular saves to salvage a draw as the Bollaert-Delelis stadium.
Lille are sixth on 45 points.
Monaco will leapfrog Lens into third if they beat Troyes away on Sunday while fifth-placed Rennes host second-placed Olympique de Marseille.
"The first half was ours but we sat up too much in the second," said Lens midfielder Adrien Thomasson.
"We did not manage to be on top of things during the whole game."
Lille had handed Lens their first defeat of the season last October so Lens were clearly out for revenge.
Lille dominated possession but Lens looked sharper and they were rewarded in the 41st minute when Fonte deflected Angelo Fulgini's free kick into his own net.
The visitors levelled in the 69th minute when David poked the ball home from point-blank range after Samba made two outstanding saves to deny Jonathan Bamba and Remy Cabella.
Later on Saturday, leaders Paris St Germain take on Nantes.