Paris Saint-Germain went top of Ligue 1 for the first time this season after title-rivals Lyon lost 2-1 at home to ten-man Nice on Saturday.
The Parisians beat Lorient 3-1 on Friday thanks to a hat-trick from their giant Swedish striker Zlatan Ibrahimovic.
The result leaves PSG on 59 points from 30 games with Lyon, who had taken the Ligue 1 lead from Marseille in the first game of 2015, second a point behind.
Marseille, who are five points behind PSG in third, travel to Lens on Sunday night.
If Marseille win they would draw to within a point of Lyon, and two of PSG, to send Ligue 1 into a three-way battle of nerves with just eight games to go.
Lyon coach Hubert Fournier accepted his side, rich in players from their youth academy, might have made a critical blunder.
"We've lost three points at a crucial part of the season," he said. "And you can't just say 'Oh well get them back later on'."
"But how can you be angry when your forward line has an average age of 21 years, and your entire team lacks the depth of experience to deal with the pressure of that kind of game," he added.
"We knew it could be tricky with Nice battling relegation, while we were playing without some of our senior players."
Lyon had their star striker and talisman Alexandre Lacazette suspended for the match but visitors Nice were reduced to ten men when Lloyd Palun was sent off on 56 minutes.
The resulting penalty saw Maxime Gonalons equalise from the spot after the visitors had gone ahead when Carlos Eduardo converted a corner in acrobatic fashion on 23 minutes.
But a late penalty saw Nice reclaim the lead on 86 minutes with Valentin Eysseric stepping up to clinch three points and topple Lyon from the summit.
Claude Puel, the ex-Lyon coach now at the helm of Nice, had no sympathy for his former club as his Riviera outfit notched up vital points in the battle against relegation.
"The relegation battle is still going to be close," said Puel, whose side are now provisionally eight points above the first relegation spot.
"And in terms of the title race that'll slow Lyon down and I'm happy about that because it means we won, and won with quality football despite everything."
Source: AFP