Paris Saint-Germain suffered their fourth defeat in Ligue 1 after going down 3-0 to Monaco in Le Classique on Sunday afternoon.
PSG made two changes to the side that thrashed Bordeaux, as Lionel Messi was not in the squad due to flu-like symptoms while Marco Verratti and goalkeeper Gianluigi Donnarumma were both recalled.
Monaco had a bright start as they created a couple of clear opportunities and came the closest to going ahead in the 21st minute after Gelson Martins went through on goal on the right wing and played a cut back that was well hit by Jean Lucas but Donnarumma made a fine save.
The hosts eventually broke the deadlock four minutes later after Wissam Ben Yedder found the back of the net with an audacious back-heel at the near post after a low cross by Youssouf Fofana.
Mauricio Pochettino's charges got into the game after that, asking Monaco plenty of questions, as Neymar had a threatening free-kick on the half-hour mark that forced a save out of shot-stopper Alexander Nubel and Mbappe also lacked the finishing touches, as he spurned a couple of chances.
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The Parisians continued to threaten in the early stages of the second stanza, as Mbappe had a shot cleared off the line by Benoit Badiashile.
However, PSG's momentum slowed down after the hour-mark and they were punished in the 68th minute after Kevin Volland, who had just come on finished off a cross by Ruben Aguilar with a strike towards the bottom corner after making a deep run in the box.
Pochettino made attacking changes after that, as Mauro Icardi replaced Georginio Wijnaldum and Neymar made way for Julian Draxler.
Monaco were dangerous on counter-attacks and they were awarded a penalty nine minutes before time after Presnel Kimpembe brought down Volland, who was going through on goal in the box.
Ben Yedder put the game to bed for Philippe Clement's troops with a low strike from the spot-kick that was initially parried by Donnarumma but the ball bounced off the post and ricocheted off the opposite post before crossing the line.
PSG were denied a consolation goal in the dying minutes but they remained 15 points clear at the top of the log, although their lead could be cut to 12 points if either Marseille or Nice get maximum points in their clash later in the evening.