Ligue 1 leaders Monaco had to come from behind to draw 1-1 away to Bastia on Friday evening and missed the chance to go six points clear.
Sadio Diallo had given the struggling Corsicans the lead in the first half before Bernardo Silva headed Monaco level early in the second period.
The result maintains Monaco's unbeaten record in 2017 and extends their lead at the top of the table to four points from Paris Saint-Germain.
However, a buoyant PSG, fresh from their huge Champions League win over Barcelona on Tuesday, can close to within a single point of the Principality side if they beat Toulouse at home on Sunday.
Monaco had won their last nine top-flight meetings with Bastia and the Corsicans had gone seven matches without a win in all competitions coming into this one.
They remain in the relegation zone but can be the happier side with the result, despite failing to hold onto the lead given to them by Diallo in the 18th minute.
Gael Danic crossed from the back post for Diallo to head towards goal at the back post. Monaco goalkeeper Danijel Subasic got down low to claw the ball away, but goal-line technology confirmed the effort had already crossed the line.
A below-par Monaco drew level seven minutes into the second half when Almamy Toure crossed from the right and Portuguese international Silva stooped to head home.
However, they could not get the win ahead of their trip to Manchester to face Pep Guardiola's side in their Champions League last-16 first leg next Tuesday.
The draw will also boost the title hopes of Nice, who are third and can close to within three points of their Cote d'Azur neighbours with a win at bottom side Lorient on Saturday night.