A Diego Carlos brace and Majeed Waris’ tap-in inflicted a third league loss on Thomas Tuchel’s side, who were hammered 5-1 at second-placed Lille on Sunday and drew with Bordeaux the previous week, despite Dani Alves’ stunning opener and substitute Metehan Guclu pulling one back late on.
However PSG, who were without dropped Kylian Mbappe and missing a host of other first-team players through injuries and suspension, remain 17 points clear with six games left and could still win their sixth title in seven years at the weekend.
Depleted PSG had to thank Gianluigi Buffon 12 minutes in when he managed to push away Kalifa Coulibaly’s header from point-blank range, and seven minutes later Alves appeared to have calmed Parisian nerves with his wonder strike.
There looked to be little on when the Brazilian collected Leandro Paredes’ simple pass, but he quickly lashed an unstoppable dipping drive past Maxime Dupe to score his first Ligue 1 goal this season.
However just three minutes after the opener Diego Carlos was allowed too much space to nod home Valentin Ronger inswinging corner.
PSG continued to struggle despite the odd flash from Moussa Diaby, and the hosts grabbed a deserved second just before the break.
Coulibaly was at the heart of it, brushing Thilo Kehrer off the ball on the left flank, before cutting back to Samuel Moutoussamy, whose mis-hit shoot evaded the dozing PSG defence and found Waris for the simplest of tap-ins.
Nantes turned the screw seven minutes after the break from another corner, this one met by a Nicolas Pallois flick-on that crept through a sea of legs to Carlos, who unwittingly knocked in the third.
Without Mbappe to pressure them, Nantes kept coming forward, and were almost gifted a fourth in the 68th minute when Paredes passed the ball straight to Coulibaly with Buffon way out of his goal, only for the Malian to hit his shoot too hard and over the bar.
Guclu crashed home his first ever PSG goal in the final minute to give the away side hope that they could still clinch the title with six matches to spare, but despite pressing forward they couldn’t find the breakthrough.
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