Belgian midfielder Eden Hazard scored the winner in injury time Sunday as Lille beat Valenciennes 2-1 in the northern derby to move three points clear at the top of the French league table.
Moussa Sow had given Lille the lead in the 39th minute, before Gregory Pujol equalized in the 59th.
Following a Valenciennes defensive mistake in added time, the 20-year-old Hazard scored with an angled shot after controlling the ball and turning to shoot.
Lille earned its second straight league win after beating Marseille by the same score last weekend and is now three points ahead of second-place Rennes.
Also Sunday, striker Olivier Giroud scored a brace as Montpellier overcame a two-goal deficit to draw 2-2 at Paris Saint-Germain. Monaco left the relegation zone to climb to 17th place with a 1-0 win at Bordeaux.
In a very tight race for the title, third-place Lyon trails Lille by four points, leading Marseille on goal difference.
Sow, the league's stop scorer with 18 goals this season, put Lille in front with a shot deflected by a defender after Hazard had put him in a good position.
Valenciennes striker Pujol scored the equalizer in the 59th from Renaud Cohade's fine pass and Lille looked poised for a disappointment until Lille captain Rio Mavuba found Hazard unmarked in the box with seconds left to play.
Hazard has been one of the league's best players this season and has attracted interest from European clubs such as Real Madrid and Arsenal.
"I scored two nice goals (against Marseille and Valenciennes) but I need to score again and provide some more assists if I want to reach another level," Hazard said. "So much the better for me and the team, those two goals are very important."
Monaco defender Adriano gave his team three much-needed points in the 20th minute when he jumped higher than the defenders to head home Vincent Muratori's corner.
Benoit Tremoulinas nearly equalized in the 31st minute, following a one-two with Brazilian midfielder Wendel, but his shot hit the post.
PSG's France striker Guillaume Hoarau broke the deadlock in the 11th minute against Montpellier at the Parc des Princes, two minutes before Montpellier's Mapou Yangambiwa scored an own goal.
Giroud pulled a goal back two minutes into the second half by heading home a corner but Montpellier was reduced to 10 men a minute later after Cyril Jeunechamp was sent off for a second yellow card.
PSG couldn't build on the momentum and struggled physically as Giroud scored the equalizer in the 58th minute with an angled left-foot shot.
Fifth-placed PSG lost ground in the title race and now trails fierce rival Marseille by three points ahead of their encounter next weekend at the Stade Velodrome.
On Saturday, Lyon warmed up for its trip to Real Madrid in the last 16 of the Champions League with a 2-0 win at Sochaux while Marseille won at Rennes on Friday ahead of its match at Old Trafford against Manchester United.
