Belgian striker Michy Batshuayi netted a half-volley in the 69th minute as Marseille ensured they stayed top of the table heading into the two-week winter break.
Batshuayi, who was given the nod ahead of Dimitri Payet after the Frenchman was dropped by coach Marcelo Bielsa due to poor training performances, controlled Florian Thauvin's cross before turning and firing the ball into the top corner of the net.
The match-winner came eight minutes after Idrissa Gueye equalised for Lille, cancelling out Marseille's first-half opener at the Stade Velodrome.
Marseille hit the front fortuitously in the 32nd minute when Lille's Nolan Roux sent the ball into his own net.
Bielsa's Marseille enjoy a two-point buffer atop the table, ahead of Lyon, who were big winners on Sunday as they leapfrogged defending champions Paris Saint-Germain into second spot.
Frenchman Alexandre Lacazette bagged his third consecutive league brace as Lyon humiliated 10-man Bordeaux 5-0 away from home to move a point clear of PSG.
League-leading goalscorer Lacazette (17), who has scored more goals than Zlatan Ibrahimovic and Edinson Cavani combined, broke the deadlock with a curled effort six minutes before half-time.
Corentin Tolisso doubled the lead 11 minutes after the break, placing the ball beyond Bordeaux goalkeeper Cedric Carrasso.
Bordeaux were reduced to 10 men in the 65th minute when Nicolas Pallois was sent off for a challenge on Clinton N'Jie.
And Lyon made the most of their numerical advantage, with Nabil Fekir, Jordan Ferri and Lacazette all on target during the final nine minutes.
Saint-Etienne are three points beyond Lille and five adrift of Marseille thanks to a comfortable 3-0 victory over third-bottom Evian TG.
Evian TG were no match for the in-form Saint-Etienne, who were led by goals to Mark Gradel, Ricky van Wolfswinkel and Romain Hamouma.
