Paris - Marseille's title hopes took a significant blow after coach Marcelo Bielsa's team threw away a 2-0 lead in a 3-2 home loss to Caen on Friday.
The defeat means that third-placed Marseille stays on 50 points, four adrift of league leaders Lyon and two behind defending champion Paris Saint-Germain.
Marseille seemed set for a confidence-boosting win after Ghana winger Andre Ayew put the home side ahead shortly before the interval and top scorer Andre-Pierre Gignac pounced for his 15th league goal of the season in the 63rd minute.
But 35-year-old midfielder Nicolas Seube pulled a goal back four minutes later, striker Emiliano Sala leveled in the 70th with his fifth league goal in six games, and midfielder Nicolas Benezet sealed the win in the 87th.
"This match was totally within our reach," Bielsa said. "But after we scored our second goal, they had three attacks and scored three times. From that point onward we didn't attack well or defend well."
Marseille has drawn three and lost one of its past four league games and Bielsa is blaming himself for the team's inability to put teams away. Last weekend, Marseille rallied from behind to lead 2-1 away to Saint-Etienne, only to concede a clumsy equalizer deep into injury time.
"The amount of players we have in the opponent's half means that it's difficult to win the ball back and it reduces our possibility to defend well," Bielsa said. "It wasn't really so noticeable in the first half of the championship but it's more evident now."
Bielsa started with 21-year-old striker Michy Batshuayi ahead of Gignac, who was relegated to the bench against the Normandy side.
Batshuayi came off the bench to score twice in quick succession against Saint-Etienne, while Gignac had scored only once in his previous five games and was reportedly involved in a heated argument with Bielsa during training this week.
That decision had looked set to pay an instant dividend when the hosts were awarded a spot kick in the third minute after Batshuayi was felled in the box. However, the striker saw his penalty saved by goalkeeper Remy Vercoutre.
Gignac, who has broken back into the France squad and is now just four goals short of reaching 100 career league goals, replaced Batshuayi in the 59th and just four minutes later doubled his side's lead.
"He did very well. He's a born goal scorer," Bielsa said. "He bought a lot of dynamism to our attack."
League leader Lyon is away to Lille on Saturday, while PSG travels to fourth-place Monaco on Sunday night. PSG will be without top scorer Zlatan Ibrahimovic, who is suspended for that game and the French Cup quarterfinal, also against Monaco, three days later.
Caen is provisionally in ninth place ahead of this weekend's other games.