Florian Thauvin and Rod Fanni scored as the Ligue 1 leader extended the gap atop the table.
Marseille beat Nantes 2-0 on Friday to go four points clear at the top of Ligue 1 and put the pressure back on Paris Saint-Germain.
Defeats to PSG, Rennes and Lyon in their last five matches put Marseille's position at the top of the table under threat, but it was given few problems by in-form Nantes at Stade Velodrome.
Florian Thauvin broke the deadlock after 24 minutes, as the winger raced in front of his marker at the near post and directed Dimitri Payet's cross in with a delightful flick of his left foot.
Nantes, who went into the match on the back of a 10-match unbeaten run in all competitions, should have drawn level in the 36th minute, but Steve Mandanda made a fine save on George N'Koudou.
And Marseille capitalized just three minutes later, as Rod Fanni guided Thauvin's delivery beyond the helpless Remy Riou with the back of his head.
Fourth-place Nantes improved in the second half, but Marseille held on with relative comfort ahead of PSG's clash with Nice on Saturday.