Paris St Germain's title march towards the Ligue 1 title suffered another setback when they suffered a 1-0 home defeat by Olympique Lyonnais on Sunday.
The capital side, who only have the league to salvage a disappointing season after being knocked out of the French Cup and the Champions League, fell victim of Bradley Barcola's second half goal and were left on 66 points from 29 games.
They lead second-placed RC Lens, who beat Stade Rennais 1-0 away on Saturday, by six points with third-placed Olympique de Marseille also on 60 points after a 1-1 draw with Montpellier on Friday.
Earlier on Sunday, fourth-placed Monaco moved within three points of Marseille after a spectacular 4-3 home victory against Racing Strasbourg.
Lyon are ninth on 44 points.
The clash between PSG and Lyon started 10 minutes late after Laurent Blanc's side faced transportation issues.
"We could no go under a bridge so we drove all around Paris," OL assistant coach Ludovic Giuly said.
The delay did not disturb Lyon.
They were awarded a penalty when Gianluigi Donnarumma made contact with Alexandre Lacazette in the area after a sharp counter attack from the visitors.
Lacazette, however, hit the Italian keeper's right-hand post for the French striker's first miss from the spot this season.
PSG, who had their best chance in the opening half through Renato Sanches, were denied a penalty themselves on the stroke of the interval despite Dejan Lovren's handball and they fell behind on 56 minutes.
Barcola connected with Sael Kumbedi's cross to finish it off with a soft crossed shot to give Lyon the advantage.
PSG failed to react as they could not manage a shot on target before Hugo Ekitike's attempt was easily blocked by Anthony Lopes while Kylian Mbappe failed to make much of an impact.
The France forward had his best chance in the first minute of stoppage time with a deflected shot that was tipped away by Lopes.
OL held firm until the final whistle and will head into Wednesday's French Cup semi-final full of confidence while PSG, who were handed their fifth league defeat of the season, will need to regain their composure with a top-of-the table clash against Lens in two weeks.