Lyon's Ligue 1 title bid took a huge blow as they suffered a second straight defeat, a surprise home loss to Lille.
Coming on the back of last week's reverse away to lowly AC Ajaccio, today's result leaves them six points adrift of Paris St Germain who have suddenly found themselves coasting after poor results for both Lyon and Marseille since the winter break.
Aurelien Chedjou headed the visitors in front after 28 minutes and then doubled their advantage through Florent Balmont seconds before the break, converting Lyon coach Remi Garde's half-time address into crisis talks.
But whatever he said did little good as Salomon Kalou fired in a penalty five minutes into the second half.
Lisandro Lopez got one back from the penalty spot seven minutes later but nothing would come for Les Gones in open play and Lille saw the game out.
Lille were bright from the start, and Dimitri Payet might have given them a deserved lead in the 18th minute when he raced free on to Kalou's pass, only to slip the ball wide of Remy Vercoutre's net.
The breakthrough came when Chedjou headed in Payet's corner, provoking the first real attacks from Lyon in response.
Steed Malbranque teed up Lisandro, but Steeve Elana punched the shot away. Lisandro then turned provider, crossing for Clement Grenier to head goalwards but Elana was again equal to it.
Lille then scored a devastating second in the final moments of the half as Payet's pass split the defence and Balmont shot across the face of goal.
When Milan Bisevac handled early in the second half, Kalou all but killed off Lyon as he sent Vercoutre the wrong way from the spot.
Lisandro's penalty gave them a lifeline after Franck Beria fouled the Argentinian forward but 10 minutes later Elana made an outstanding save to keep out Bafetimbi Gomis' volley, and Lille then re-established control of the match.
There were late chances for Marvin Martin and Payet - the latter striking the post after neat play with Kalou - but the visitors had already done enough to add another twist to the title race.