Brazilian winger Nene scored one goal and created two more as Paris Saint-Germain hit back from conceding two early goals to win 4-3 at Valenciennes on Sunday and move level with Montpellier at the top of the French league.
Montpellier can restore its three-point lead by winning at fifth-place Rennes on Monday. Both teams will then have two matches left.
PSG's shaky defense was exposed again when it trailed 2-0 inside 11 minutes, both goals the result of poor marking.
Nene pulled a goal back four minutes later, set up Maxwell for the equalizer and then provided Jeremy Menez with a fourth goal.
PSG is bidding to win the French title for the first time since 1994 and the third time overall. Montpellier has never won the league.
Valenciennes took the lead in the eighth minute.
A long ball over the top to striker Vincent Aboubakar landed in between central defender Alex and left back Maxwell, with neither reacting quickly enough. Alex moved across too late and Aboubakar had time to turn and shoot low past goalkeeper Salvatore Sirigu.
Maxwell was exposed again as Aboubakar was given too much space again and, although Sirigu saved his effort, the ball fell for Remi Gomis to tap in for 2-0.
''We started really badly and it took that second goal for us to get back in the game,'' PSG midfielder Blaise Matuidi said.
But Valenciennes defended even more poorly and left gaps everywhere.
Winger Jeremy Menez collected a poor clearance from right back Rudy Mater and clipped the ball into the path of Nene, who finished with a strike into the opposite corner for his 18th league goal of the season in the 15th.
Nene then turned provider, holding the ball up on the edge of the penalty area and then releasing it perfectly into the path of Maxwell, who beat goalkeeper Nicolas Penneteau inside his near post for his first PSG goal since joining from Barcelona in January.
Playmaker Javier Pastore then showed superb vision to slide the ball toward Matuidi, and he poked the ball past Penneteau for 3-2.
''We played well in the first 20 minutes, but after that we didn't defend well,'' Valenciennes midfielder Gael Danic said. ''If you leave gaps like that against PSG you get punished for it.''
The warning was not heeded as PSG scored again in the 58th.
Pastore, the French record signing at €42 million, showed a touch of genius leading up to the goal. He controlled a long ball with the back of his heel, turned toward goal and then found Nene, who flicked the ball left and Menez stroked it wide of Penneteau's arm.
Valenciennes ensured a nervous last 10 minutes for PSG when midfielder Renaud Cohade curled a freekick into the top corner.
