Paris St Germain missed an opportunity to move top of the Ligue 1 standings when they suffered an embarrassing 2-1 home defeat against strugglers Nantes on Sunday.
Nantes' Randal Kolo Muani cancelled out Julian Draxler's first-half opener after a Kylian Mbappe blunder before Moses Simon scored in the 71st minute to stun the champions.
After their seventh league defeat of the season - the fourth at the Parc des Princes - PSG are second with 60 points from 29 games, three behind Lille who drew 0-0 at AS Monaco as none of the top four teams won at the weekend.
The result lifted relegation-threatened Nantes to 18th place on 27 points, a point below Lorient and the safety zone.
Four days after a lacklustre display in a Champions League draw with Barcelona in the last-16, where they progressed due to a big first-leg lead, PSG struggled again but Draxler opened the scoring three minutes from the break with a low shot.
Shortly before the hour, Nantes deservedly equalised as a poor pass by Mbappe virtually set up Kolo Muani, who beat goalkeeper Keylor Navas from close range.
After a brief discussion with PSG sports director Leonardo, coach Mauricio Pochettino replaced Angel Di Maria with Leandro Paredes after 62 minutes and went towards the dressing room with the Argentine before coming back to the bench.
In the 71st minute, Kolo Muani set up Simon, who rifled home to put the visitors ahead.
It finally spurred PSG into action, but Alban Laffont made a couple of good saves to preserve Nantes's advantage until the final whistle.
Earlier, Lille's seven-game winning streak on the road ended when they failed to break the deadlock at Monaco in a 0-0 encounter at Louis II.
Monaco and Lille failed to create decent chances, until Stevan Jovetic was denied by Lille keeper Mike Maignan's superb save in stoppage time.
Monaco are fourth on 56 points, four behind PSG and third-placed Olympique Lyonnais, who were held to a 1-1 draw at Stade de Reims on Friday.