Lille suffered a 2-1 home defeat against lowly Nimes on Sunday and were knocked off top spot in Ligue 1 as their title campaign continued to stutter.
Xeka cancelled out Moussa Kone's early opener for the visitors but Renaud Ripart gave Nimes all three points and left Lille on 63 points from 30 games.
Christophe Galtier's side are now second on goal difference behind champions Paris St Germain, who moved top thanks to a 4-2 win at third-placed Olympique Lyonnais.
Nimes's victory lifted them a spot up to 18th, on 29 points.
Lille, who have won only two of their last six league games, were caught off guard early as Kone curled a superb 20-metre shot into the top corner to put the visitors ahead on 12 minutes.
It did not take Lille long to react.
In the 20th minute, Xena equalised with a downward header from Jonathan Bamba's corner.
Nimes, however, restored their advantage just before the break, with Ripart chipping the ball past Mike Maignan after being played through by Zinedine Ferhat.
Lille had two goals, by Burak Yilmaz and Xeka, disallowed as they pushed for a late leveller.
(Reporting by Julien Pretot; Editing by Toby Davis)
