Veteran midfielder Benjamin Nivet punished some sloppy defending in the 89th minute when he swept in a loose ball to give Troyes its first win of the season to lift it off the bottom of the table.
Marseille has picked up only one point from its last three games to put PSG back in the title race, having been six points ahead of its bitter rival a few weeks ago.
”We didn’t do enough to win it, we had chances to score and we paid for it,” right back Rod Fanni said. ”It will be a lesson for us. To lose the way we did means we didn’t give enough at the end, because we still had a lot of energy left. They got their chance and took it.”
Marseille was dealt a further blow when top scorer Andre-Pierre Gignac landed heavily after challenging for a header in the first half and hurt his left foot. Despite treatment and strapping, he was unable to continue and Loic Remy replaced him up front. The club later said Fanni fractured his foot.
Shortly after Gignac went off, Marseille almost took the lead when winger Morgan Amalfitano’s low shot drew a smart save from goalkeeper Yohann Thuram-Ulien after being expertly put through by Mathieu Valbuena.
Thuram-Ulien was the busier goalkeeper and made a fine save to keep out Valbuena’s curling free kick early in the second half.
Troyes did not threaten until Nivet’s header hit the crossbar in the 60th, and moments later Remy missed a point-blank header after being perfectly set up by Valbuena.
Marseille should have been given a penalty with 10 minutes remaining when Remy was tripped as he prepared to shoot. Remy had a goal disallowed in injury time for offside, although this time it was the correct decision.
Earlier, striker Bafetimbi Gomis scored early in the second half as Lyon beat Brest 1-0 to reclaim third place.
”We hadn’t won our past three games so we had to win at home,” Lyon midfielder Maxime Gonalons said. ”We’re already looking forward to the Marseille game (next Sunday).”
Brest goalkeeper Alexis Thebaux kept out efforts from forwards Alexandre Lacazette and Lisandrop Lopez and from center half Dejan Lovren, while Lyon winger Jimmy Briand hit the crossbar in a one-sided first half.
Brest forward Eden Ben Basat looked sharp but hardly received any service.
Gomis finally broke the deadlock in the 57th minute when he ran onto midfielder Steed Malbranque’s clever pass and lobbed Thebaux for his fifth league goal of the season.
”Brest defended very deep and was very compact,” Lacazette said. ”We made the difference when they started to get tired.”
Lopez missed a late chance to make it 2-0 after shooting wide when under pressure from two defenders.
Lyon is two points ahead of fourth-place Toulouse, and one point behind Marseille and PSG.
Also, Ajaccio drew 0-0 with Bastia in an ill-tempered Corsican derby which saw both sides finish with 10 men and opposing fans fighting in the stands.
In a game of few chances, Ajaccio had the better opportunities and veteran Romania forward Adrian Mutu hit the post just before halftime after being set up by strike partner Eduardo. Moments earlier, Ajaccio midfielder Johan Cavalli’s deflected shot was cleared off the line.
Bastia forward Anthony Modeste went close with a header early in the second half, before Ajaccio defender Carl Medjani also saw his header hacked off the line.
With 10 minutes remaining, Cavalli was embroiled in a tussle with Bastia midfielder Gael Angoula and players from both teams joined in the melee. Both players were sent off and the incident triggered some fighting between rival supporters and some flares were also let off.
Cavalli said he had made peace with Angoula.
”You shouldn’t make too much of it,” he said. ”Gael Angoula and I spoke to each other afterward. The incident is over.”