A weakened Paris Saint-Germain were beaten 3-1 by Monaco in Ligue 1 on Saturday, three days before facing Bayern Munich in the Champions League.
Monaco climbed to second place with the victory, seven points behind a rattled PSG, who were missing Lionel Messi and Kylian Mbappe through injury.
Undefeated in all competitions from August to December, PSG lost to Lens and Rennes in the league last month and were knocked out by Marseille in the last 16 of the French Cup on Wednesday.
Wissam Ben Yedder scored twice for Monaco. His blocked shot rebounded for Aleksandr Golovin to beat PSG goalkeeper Gianluigi Donnarumma in the fourth minute.
Ben Yedder doubled the lead in the 18th minute as Monaco pressed high up the pitch. Krepin Diatta dispossessed El Chadaille Bitshiabu and Ben Yedder buried an angled strike into the far corner.
Teenage midfielder Warren Zaire-Emery pulled one back for PSG by tapping home a low cross from Juan Bernat.
But Ben Yedder restored Monaco’s two-goal lead moments before halftime with a curling shot off the post, taking him level with Reims striker Folarin Balogun as the top scorer in the league with 14.
Monaco managed the game in the second half and Donnarumma saved a low effort from substitute Takumi Minamino in stoppage time.