Ten-man Monaco lost further ground on Ligue 1 leaders Nice as they suffered a disappointing 3-1 home defeat to Lyon.
The hosts could easily have had two goals inside the opening 10 minutes but Anthony Lopes made a superb save with his foot to deny Bernardo Silva before denying his compatriot again on the follow-up.
Danijel Subasic was next to be worked as Nabil Fekir's direct free-kick threatened, but the Croatia goalkeeper got a firm hand to turn his effort away.
Then, with almost half an hour played, Subasic was beaten in the Monaco goal when Mathieu Valbuena found Rachid Ghezzal and did the rest from just inside the area.
Monaco's evening took a further turn for the worse when Benjamin Mendy was given his marching orders on 39 minutes for a kick-out at Corentin Tolisso.
Lyon looked to make full use of the man advantage and only another smart stop from Subasic prevented Ghezzal doubling his tally for the evening.
The visitors should have doubled their lead on 56 minutes when Fabinho fouled Alexandre Lacazette inside the area but, from the resulting penalty, Subasic gathered Lacazette's weak effort.
Valbuena saved Lacazette's blushes, though, when he confidently finished beyond Subasic on 65 minutes after Ghezzal returned the earlier favour from his team-mate.
Monaco were offered hope soon after when some good work from Nabil Dirar and Thomas Lemar teed up Tiemoue Bakayoko to beat Lopes with the aid of Lucas Tousart's defelction.
That hope turned to despair, though, with less than five minutes left to play when Lacazette made up for his earlier penalty miss with a turn-and-volley after Subasic had palmed a corner into his path.