Kylian Mbappe made his return from a post-World Cup holiday but Paris Saint-Germain went down 1-0 away to Rennes in Ligue 1 on Sunday, a result which leaves them just three points clear at the top of the table halfway through the season.
Rennes captain Hamari Traore scored the only goal of the game in the 65th minute in the rain in Brittany to condemn PSG to a second successive away league loss after they went down 3-1 at second-placed Lens on New Year's Day.
Prior to that they had gone unbeaten through their first 23 matches this season in all competitions and this latest loss gives their rivals hope in the title race.
This was the first time that Mbappe, Lionel Messi and Neymar had appeared on the pitch together since PSG's superstar attacking trio returned from the World Cup.
Messi had been afforded an extended holiday after guiding Argentina to glory in Doha and scored on his return in a 2-0 win against Angers in midweek.
Mbappe, scorer of a hat-trick for France in the World Cup final as they lost on penalties to Argentina, had played in his club's first two games after the tournament before missing their last two as he took a holiday in New York with teammate Achraf Hakimi.
He was expected to start on Sunday but instead began the game on the bench as the 20-year-old Hugo Ekitike played in front of Messi and Neymar.
Without their leading scorer PSG were blunt up front and Rennes goalkeeper Steve Mandanda did not have a save of note to make until he kept out a Danilo Pereira header three minutes into the second half.
Mbappe replaced Ekitike in the 56th minute and did so to applause from the home fans, who were keen to show their appreciation for the striker's performances at the World Cup.
Yet Rennes went ahead soon after thanks to their Malian right-back Traore and Mbappe -- making his 200th Ligue 1 appearance -- then squandered a chance to equalise when he burst through on goal but blazed over with just the goalkeeper to beat.
With Neymar again ineffective and Messi not having the expected impact, it was Juan Bernat who came closest to equalising for PSG with a shot that was tipped over by Mandanda.
PSG coach Christophe Galtier will hope his attacking trio can rediscover their early-season form quickly with a Champions League last-16 showdown with Bayern Munich now just a month away.
Rennes, who recently lost top scorer Martin Terrier for the rest of the season with a serious knee injury, have now won nine successive home league games.
They are fifth in the table, behind Monaco in fourth only on goals scored after the principality side crushed Ajaccio 7-1 earlier in the day.