Paris Saint-Germain suffered its first defeat of the season when it was beaten 2-0 at Stade Rennais on Sunday to drop its first Ligue 1 points of the season.
Rennes won thanks to goals by Gaetan Laborde and Flavian Tait each side of the interval to end PSG's eight-game winning run in the league.
PSG, beaten in the pre-season Trophy of champions by Lille, stayed top of the standings with 24 points, six ahead of second-placed RC Lens which beat Stade de Reims 2-0 on Friday.
Rennes moved up to seventh on 12 points.
Five days after an impressive win over Manchester City in the Champions League, PSG got off to a lively start but lacked sharpness as Neymar skied a close-range attempt over the bar in the 22nd minute.
Lionel Messi's 25-metre free kick crashed against the crossbar and although he combined well with Neymar and Kylian Mbappe, the visitor struggled to break the deadlock.
Rennes, which had less than 72 hours to recuperate after beating Vitesse Arnhem in the Europa League on Thursday, went ahead on the stroke of halftime in clinical fashion.
Laborde netted his sixth goal of the season by volleying home from Kamaldeen Sulemana's cross.
Having failed to manage a single shot on target in the first half, PSG was caught cold straight after the interval as Tait fired home from Laborde's cross.
The hugely disappointing Neymar was substituted by Mauro Icardi in the 76th minute but the Argentine failed to inspire PSG who also failed to muster a shot on target in the second half.
Rennes kept its composure in the closing stages as it handed PSG its first away league defeat for eight months.
In the other games, Lille handed Olympique de Marseille its second consecutive Ligue 1 defeat when Jonathan David's double gave it a 2-0 home win on Sunday as the visitor finished with 10 men.
David struck after 28 minutes and again deep into stoppage time to lift the French champion to eighth in the standings on 14 points from nine games as it continues to recover from a bad start to the season.
The result left Marseille, which suffered its first loss in the league last weekend against RC Lens, in fifth place also on 14 points, although the Provence side has a game in hand.
Lille, which has now won its last three Ligue 1 games, broke the deadlock when David latched onto Mehmet Zeki Celik's cross.
It had a chance to double the advantage after 74 minutes but Jonathan Ikone's strike crashed against the bar, three minutes before Cengiz Under was sent off for Marseille after picking up a second yellow card.
David wrapped up the points after five minutes of added time from point-blank range.
- Deodhar Trophy 2023 LIVE Score, Round 1: South 209/3 (36 overs) Jagadeesan, Bhui rebuild; Utkarsh fifty leads East chase
- Australia coach McDonald dismisses ‘far-fetched’ Cummins resignation talk
- Japan Open 2023: Satwik-Chirag pair eyes another title; focus on Sindhu, Prannoy
- Aiming for more at Asian Games: IOA at crossroads to send more teams from India to Hangzhou 2022
- ISL 2023-24: Jamshedpur FC signs Japanese midfielder Rei Tachikawa