Lille's hopes of retaining their Ligue 1 title suffered a severe blow when they were sunk by two goals from Loic Remy in a 2-0 defeat at Olympique Marseille on Sunday.
France striker Remy rewarded Marseille's domination as Didier Deschamps's side continued their impressive run and stayed on track for a Champions League spot next season.
Third-placed Lille, who have 36 points from 20 games, now trail Paris St Germain by seven points after the leaders beat Toulouse 3-1 on Saturday.
Marseille, who have won seven and drawn two of their last nine games in all competitions, are sixth and two points adrift of Lille.
"We scored two nice goals and kept a clean sheet," coach Deschamps told Canal Plus television after his side inflicted Lille's first league defeat for five months.
"Our game is more simple now," he added referring to Marseille's direct approach. "It is important to continue like this."
While the home team were minus brothers Jordan and Andre Ayew, on African Nations Cup duty with Ghana, Lille were without Senegal striker Moussa Sow who is preparing for the same competition.
Marseille controlled possession but Mickael Landreau was not tested in goal until the 21st minute when he parried a Remy volley from a delightful Mathieu Valbuena cross.
On the stroke of halftime Remy broke down the right flank and his centre was met by a volley from Benoit Cheyrou that was saved by Landreau.
Cheyrou suffered a knock early in the second half and was replaced by Brandao who is back from a loan spell in Brazil.
Marseille went ahead in the 61st minute when Remy headed in a centre from Valbuena.
Remy then made it 2-0 with seven minutes to go, beating Landreau at the end of an unchallenged 40-metre solo raid.
"The teams coming to the Stade Velodrome now fear us. That was not the case before," he said before denying he would leave Marseille during the January transfer window.
Remy has been linked with a move to Tottenham Hotpsur and the London club's manager, Harry Redknapp, was spotted in the crowd on Sunday.