The league leaders maintained the four-point advantage they had taken into the weekend with Florian Thauvin scoring the winner on the hour mark, although Alaixys Romao's second yellow with 14 minutes left ensured a nervous finish for Marseille.
Romao hauled back Lens striker Pablo Chavarria in the 76th minute for a clear second caution of the match, but Marseille held on to claim their ninth win of the season.
Bordeaux also won on Sunday, overcoming Toulouse 2-1 to defeat their Derby de la Garonne rivals for the second time in six days and move into fourth, while Nantes drew 1-1 with Rennes.
In Marseille, the hosts opened the scoring in the 10th minute with Nicolas N'Koulou powering a header home from close range after a flick-on from a corner, but Baptiste Guillaume equalised just after the half-hour mark, finishing from near the penalty spot after Chavarria's shot was blocked.
Fifteen minutes into the second half, however, Marseille scored the decisive goal with Thauvin stabbing Andre-Pierre Gignac's cut-back into the top corner to secure victory for Marcelo Bielsa's men.
Marseille (28 points) lead reigning champions Paris Saint-Germain (24) in the standings with Lyon (23) in third, two points ahead of Bordeaux and Saint-Etienne (both 21).
Bordeaux moved ahead of Saint-Etienne on goal difference with another win against Toulouse, their second in a row after overcoming their local rivals 3-1 in the Coupe de la Ligue on Tuesday.
Marc Planus struck first for Bordeaux in the 52nd minute with a tap-in at the back post, while Diego Rolan's diving header 11 minutes later put the home side two goals ahead.
While Aleksandar Pesic dragged a goal back for Toulouse in the 68th minute, finishing from Martin Braithwaite's cross, the visitors were unable to avoid a fourth consecutive defeat in all competitions, slumping to 14th in Ligue 1.
Nantes (20 points) slipped to sixth after being held at home by 11th-placed Rennes, the home side having to come from behind to draw after conceding in just the fourth minute.
Get the best features, fun and footballing frolics straight to your inbox every week.
Thank you for signing up to Four Four Two. You will receive a verification email shortly.
There was a problem. Please refresh the page and try again.