Marseille laboured to a 2-0 home win against last-place Dijon on Sunday but strengthened its bid for a Europa League place after its rivals dropped points over the weekend.
The scrappy victory moved sixth-place Marseille one point behind Lens in fifth place and a Europa League spot next season. Rennes and Montpellier dropped three points behind Marseille by drawing their matches on Sunday, the day after Lens was held by Lyon.
It was a third win in four games for Marseille's new coach, Jorge Sampaoli, but he was clearly frustrated at times.
Dijon has not won this year, losing 11 straight league games and drawing the other three. Despite facing poor opposition, Marseille struggled to create anything in a drab first half.
Seconds before the break, Argentina centre back Leonardo Balerdi, who is on loan from Borussia Dortmund, headed in Dimitri Payet's corner at the near post.
Payet set up the second goal for another central defender as Alvaro Gonzalez nodded home from his free kick in the 78th.
Montpellier was held 1-1 at Angers while Rennes needed a late equalizer from striker Serhou Guirassy to draw 2-2 with Reims.
English striker Stephy Mavididi's header just after halftime earned him a ninth goal of the season for Montpellier, but Stephane Bahoken equalized for Angers in the 71st.
In other matches Sunday, it was: Lorient 1, Brest 0; Bordeaux 2, Strasbourg 3; Nantes 1, Nice 2; and Nimes 0, Saint-Etienne 2.
Denmark striker Kasper Dolberg netted twice for Nice.
Twenty years after winning its eighth league title, former league standout Nantes is 19th and deep in relegation trouble with just seven games remaining.
A hectic Saturday saw defending champion Paris Saint-Germain lose at home to Lille, which is three points clear at the top.
PSG star Neymar was sent off for the second time this season.
