Paris St Germain suffered yet another setback as they slumped to their first Ligue 1 home defeat of the season when they were beaten 2-0 by Stade Rennais on Sunday.
PSG lead second-placed Olympique de Marseille, who ended Stade de Reims's 19-game unbeaten run in the league with a 2-1 away win, by seven points, but the capital side were knocked out of the Champions League by Bayern Munich earlier this month and eliminated from the French Cup by OM in February.
That left only the league title to focus on, and Sunday's performance at the Parc des Princes exposed their shortcomings and put further pressure on coach Christophe Galtier.
Once again, their attacking plans were limited to finding Kylian Mbappe, while the defence was not up to the task in the absence of the injured Presnel Kimpembe and Marquinhos.
Rennes, who prevailed with goals by Karl Toko Ekambi and Arnaud Kalimuendo, have now beaten PSG twice this season as they moved up to fifth on 50 points from 28 games, 16 behind PSG. Monaco are fourth on 54 after beating AC Ajaccio 2-0 away earlier on Sunday. "For sure we played a very bad game. There is little to say. I'm sorry for the fans who are always there. It's not us, it's not our team," said PSG midfielder Vitinha.
"We are very, very sad because we never imagined this. The club don't deserve this. It's not enough. We have to do better in the next game.
"You get the feeling that the players didn't give it their all but that's not how I feel," said Galtier.
Mbappe had two attempts brilliantly denied by Steve Mandanda -- a fine chip by the France forward in the 26th minute and a powerful shot from inside the area five minutes from the break. Rennes, instead, made the most of their chances. On the stroke of halftime, Toko Ekambi collected a superb long pass from Benjamin Bourigeaud and fired home from just inside the box, making up for a couple of earlier bad choices.