Unai Emery suffered his first loss as Paris St Germain manager as the current champions suffered an early defeat in their defence of the Ligue 1 title with a 3-1 loss to Monaco.
First-half goals from Joao Moutinho and Fabinho put Monaco in control, and after Edison Cavani had offered PSG hope, a Serge Aurier own goal sealed victory for the home side, who moved joint top with Nice and Guingamp.
The visitors made a sluggish start and soon found themselves trailing to the principality side when Moutinho expertly guided Djibril Sidibe's delivery beyond Kevin Trapp from just inside the area.
Cavani had an opportunity to level when Aurier's pass picked out the Uruguayan but his effort failed to find the target from an inviting position.
It was proving to be a first-half of few chances but, after Bernardo Silva fired wide from a decent position, Monaco shocked Emery's men with a second goal before the break.
David Luiz was to blame and, after the Brazilian defender hauled down Jemerson inside the area, reported Manchester United target Fabinho confidently stepped up to fire the ball beyond Trapp to hand Monaco a two-goal lead at the interval.
PSG could easily have reduced the deficit 10 minutes after the restart when Cavani guided Lucas Moura's delivery into Layvin Kurzawa's path but the France international failed to find the target against his former employers.
The visitors did drag themselves back into the game with just over an hour played when Aurier's back-post header from Marco Verratti's header teed-up Cavani to net his first league goal of the season.
And Cavani could easily have levelled moments later but he was denied after meeting substitute Thomas Meunier's delivery before Adrien Rabiot failed to capitalise on the follow-up.
PSG continued to dominate and only a fine save from Danijel Subasice prevented Kurzawa from levelling after Cavani steered Angel Di Maria's pass into the defender's path.
Then, against the run of play, Monaco restored their two-goal advantage when Sidibe's cross canonned off Aurier before nestling in the PSG goal beyond Trapp.