France midfielder Aurelien Tchouameni scored twice as Monaco won at Lille 2-1 to notch an eighth-straight win and move up to second in the French league.
Monaco are level on points with Marseille but lead on goal difference ahead of the latter's game at Lorient on Sunday.
Second spot secures automatic qualification for next season's Champions League, and there are two rounds remaining after this weekend.
Tchouameni scored his first from just outside the penalty area in the 42nd minute, after being set up by Monaco's 21-goal top scorer Wissam Ben Yedder and shooting past goalkeeper Leo Jardim.
English midfielder Angel Gomes equalised midway through the second half for 10th-placed Lille, last season's champions.
Tchouameni netted again with a long-distance strike from 25 metres in the 75th after being assisted by Brazilian Caio Henrique.
Monaco have not looked back since dominating Paris Saint-Germain 3-0 at home in March, and the mid-season hiring of coach Philippe Clement to replace Niko Kovac looks like paying off.