Paris Saint-Germain took first place in the French league by scraping a 2-1 home win against Nice, and then profited from Lyon's surprise 2-1 home loss to Montpellier on Saturday.
But those results left Lille needing only a draw at home to mid-table Brest on Sunday to reclaim first place.
Lyon had won five straight games, but fell behind in the 19th minute when Montpellier midfielder Teji Savanier latched onto a superb cross from striker Andy Delort.
Brazil midfielder Lucas Paqueta equalized seconds before the interval, sweeping home from close range after Houssem Aouar's header was saved.
Savanier's free kick midway through the second half was poorly dealt with by Lyon's defense, and substitute Elye Wahi scored.
Frustrated forward Islam Slimani had two headers saved in stoppage time as Lyon pushed hard for an equalizer.
Earlier, defending champion PSG overcame an awful blunder by central defender Marquinhos to win with a late Moise Kean goal.
Marquinhos was under no pressure on the ball, but instead of clearing it he passed left across the penalty area and Rony Lopes intercepted the ball and finished with a powerful shot in the 50th minute.
Nice striker Amine Gouiri hit the crossbar 10 minutes later after the visitors sliced through PSG's defense with ease " a worrying sign given it faces Lionel Messi's Barcelona on Tuesday.
But with Nice right on top, PSG scored against the run of play when Kylian Mbappe crossed to the back post and Mauro Icardi expertly volleyed a pass to give Kean an easy header in the 75th.
Julian Draxler capped a rare appearance with a goal to put PSG ahead midway through the first half. The Germany winger slotted in from close range after Icardi slid to meet a cross and his shot bounced off the post toward Draxler.
With PSG only third in the league before the game, coach Mauricio Pochettino could ill afford to rest key players but also had to keep in mind the Champions League match against Barcelona.
Neymar is out injured for the next four weeks with an adductor injury, winger Angel Di Maria is nursing a thigh problem, and midfielder Marco Verratti is recovering from a bruised hip.
"Marco trained today, he's still feeling a bit of pain," Pochettino said. "We'll see how things develop over the next few days."
There was one bright spot, however. Goalkeeper Keylor Navas started after recovering from an adductor injury.
In Saturday's other game, sixth-placed Lens drew at struggling Reims 1-1.
Kosovo midfielder Arber Zeneli netted early for Reims and striker Florian Sotoca equalized in the second half.
While Lille seeks an eighth straight win, Monaco is also in fine form and can notch a ninth straight with a home win against 17th-place Lorient.
Lille's defense has been rock-solid, allowing only one goal in the past seven games while Monaco has conceded 10 in eight matches.
Fourth-placed Monaco will be one point behind Lyon if it wins.