But Toulouse missed the chance to join PSG and Marseille on 22 points when it lost 1-0 away to Bordeaux, with Yoan Gouffran scoring an 87th-minute winner for the home side. Toulouse stays in fourth spot, three points behind the top two.
Andre Ayew had been one of Marseille's best players during the past two seasons, scoring 18 league goals from the wing, but his form has been patchy this campaign and he netted for the first time this league campaign following a goalmouth scramble in the 55th minute.
Jordan Ayew hit his third of the season after being set up by Mathieu Valbuena in the 88th.
Marseille had lost its past three games without scoring a goal, and was knocked out of the League Cup by PSG on Wednesday, having won the competition three years in a row.
"We had to put an end to this run of defeats," Valbuena said. "It's never easy to win here. We weren't good in the first half, but we were a completely different team in the second half and we got our reward."
Marseille has played one match less than PSG, which lost 2-1 at home to Saint-Etienne on Saturday.
"The main thing was for us to draw level with PSG," Valbuena said. "We've seen that they're not invincible, it's good for our morale."
Valbuena has been Marseille's best player by far this season, and is pushing for a starting place in the France team. He was involved in both goals.
For the first, his cross found Morgan Amalfitano, whose shot was saved by Mexico goalkeeper Guillermo Ochoa. Midfielder Charles Kabore followed up by heading the loose ball back into the box and Andre Ayew buried it.
Then Valbuena picked out Jordan Ayew in the penalty area, and he kept his composure before picking his spot with a shot into the bottom corner.
Valbuena, who left to an ovation from Marseille's travelling support, almost made it 3-0 with a solo run and shot which forced Ochoa into a finger-tip save.
"Massive result on the road. Especially with PSG slipping up yesterday," Marseille midfielder Joey Barton said on his Twitter account. "Not easy in Corsica. Well done lads."
Barton did not play as he is still serving out a 12-game suspension carried over from the last day of the Premier League season after being sent off for violent behaviour against Manchester City.
Bordeaux's win moved it up to seventh in a match of few chances.
Jaroslav Plasil missed an early opportunity for Bordeaux when goalkeeper Ali Ahamada saved his low shot with his legs, while Franck Tabanou had Toulouse's best chance of the first half but blazed wide.
Bordeaux finally breached Toulouse's well-organized defence when Plasil slipped a clever ball behind the centre backs and Gouffran ran onto it and confidently planted the ball under Ahamada's body.
"I thought the ball was getting away from me a bit so I just tried to stick my foot out," Gouffran said. "We needed to bounce back after a run of draws."
Bordeaux had lost three and drawn three of its last six matches and had not won since Sept. 30.
At Stade Gerland, Lyon went 2-0 up thanks to goals from midfielder Maxime Gonalons and forward Alexandre Lacazette, but winger Whabi Khazri and midfielder Jerome Rothen replied to make it 2-2 with a goal either side of centre half Dejan Lovren's red card for Lyon.
Lisandro Lopez restored Lyon's lead with a penalty in the 56th minute after Fetih Harek was sent off for the visitors. Jimmy Briand and Steed Malbranque added goals in stoppage time.
Gonalons gave Lyon the ideal start after five minutes.
Yoann Gourcuff's free kick was met by Lovren, whose shot was saved by Brazilian 'keeper Novaes, only for Gonalons to follow up and score from close range.
Lacazette made it 2-0 in the 26th after getting on the end of Mouhamadou Dabo's cross.
Khazri pulled a goal back two minutes later and moments later Lovren was off for tripping teenage striker Florian Thauvin. Rothen coolly converted from the spot.
But Harek fouled Lacazette as he burst into the penalty area, and Lopez drilled the penalty down the middle. Harek, who was injured fouling Lacazette, was sent off and left the field on a stretcher.
The last two goals came in stoppage time, as Malbranque set up Briand and Malbranque then completed the win with another penalty after Gourcuff was fouled.
"We went through a lot of emotions in this match," Gonalons said. "It was very difficult for us when Dejan was sent off. But we stuck together, persevered and got the win."