Paris Saint-Germain's poor second half of the season continued on Sunday as the Ligue 1 leaders slumped to a 3-1 defeat at home to mid-table Lorient after having Achraf Hakimi sent off in the first half.
Lorient were already ahead through Enzo Le Fee's early goal at the Parc des Princes before Hakimi was dismissed for a second yellow card inside the opening 20 minutes.
Kylian Mbappe equalised for the home side in opportunistic fashion, pouncing to score after Lorient goalkeeper Yvon Mvogo had thrown the ball to the ground wrongly thinking the referee had blown for a free-kick.
Yet Lorient deservedly retook the lead before half-time when Darlin Yongwa converted from close range, and they made sure of the win late on when Bamba Dieng ran through unchallenged to score at the second attempt after Gianluigi Donnarumma had stopped his shot.
The final whistle was met with loud jeers from the home fans in a stadium where one end was closed as a punishment after fans let off flares during a defeat by Lyon earlier in April.
Despite their sixth Ligue 1 loss of 2023, PSG remain eight points clear at the top of the table from Marseille and on course to seal a French record 11th league title.
However, Marseille can cut that gap to five points with a win at home to Auxerre later and Lens will be six points off the top if they beat Toulouse away in midweek.
"Our second half of the season has been very, very average. Too many players seem distracted," said PSG coach Christophe Galtier, who called Hakimi's second yellow card "really stupid".
'Must do better'
"Everyone in the dressing room is disappointed, and what I expect now is a reaction from everyone, from the players, the staff and everyone who works for the club," Luis Campos, who is effectively PSG's sporting director in his role of football advisor, told broadcaster Canal Plus.
"There must be a reaction and we have to win the title. I am sure we will do it but we need to make sure we don't lose our heads. We need to be conscious of the fact we can do better and must do better."
PSG, who had Neymar watching in the stands as he continues his recovery from an ankle injury, had not lost a home league game while conceding three goals since October 2010.
That was the final season before the Qatari takeover that transformed the club.
PSG's next four games are against Troyes, Ajaccio, Auxerre and Strasbourg, four clubs who are either in the relegation zone or fighting to avoid the drop.
Their nearest rivals Marseille and Lens also play each other next weekend, and it remains highly unlikely that the Parisians might fail to retain their league crown.
Earlier, Monaco's hopes of qualifying for next season's Champions League were dealt a new blow in a comprehensive 4-0 home defeat at the hands of Montpellier.
Arnaud Nordin scored twice for Montpellier, with Faitout Maouassa and English former Arsenal winger Stephy Mavididi also on target.
It was a second successive heavy defeat for Monaco, after they went down 3-0 away at Lens last weekend.
They remain fourth in the table, five points behind third-placed Lens who do not play until Tuesday.
Only the top three in Ligue 1 qualify for the Champions League with the team in fourth going into the Europa League alongside the winners of the French Cup.
Toulouse won the French Cup on Saturday with a crushing 5-1 win over holders Nantes in the final watched by more than 78,000 at the Stade de France.
Rennes, who are sixth, boosted their hopes of qualifying for Europe by beating bottom side Angers 4-2 on Sunday with Belgium's Jeremy Doku scoring twice.
That result officially condemned Angers to relegation as they are 18 points from safety with five games to play.