PSG were joined by Liverpool as the only teams with three wins after a double from Alexis Mac Allister led a rousing 4-3 comeback win over Villarreal on Tuesday (Wednesday AEDT).
Yamal had just displayed stunning skill to level the score at 2-2 from a narrow angle when PSG took the lead again through Vitinha in Paris, before Fabian Ruiz added another for a 4-2 victory.
"We never feel like we're powerless, or that we're beaten in any way," PSG forward Desire Doue said.
"We always know there's an opportunity as long as the final whistle hasn't gone,"
Injuries to stars Ousmane Dembele and Khvicha Kvaratskhelia took some of the shine off the win for PSG, who could now face having to cope without two of their biggest difference-makers in attack.
Barcelona need to bounce back quickly ahead of a Clasico against Real Madrid on Sunday, now that their run of wins to start the season has ended.
Title-holders PSG equalled a club record by going 13 Champions League games unbeaten. Doue and Lucas Hernandez also scored for the home side.
Xavi Espart struck Barcelona's other goal.
"We made too many mistakes in this game, with the ball possession, easy ball losses," Barcelona coach Hansi Flick said.
"This was a great test for us, you saw today in which areas we have to improve to make things better."
Flick added Rodri would play on Sunday against Madrid after coming off the bench for the last half-hour.
The match took place with a visible police presence outside the stadium, against the backdrop of violent unrest across France.
At Anfield, 18-year-old Rio Ngumoha played a starring role in Liverpool's comeback, setting up goals for Ronald Araujo, Mac Allister and Florian Wirtz.
Liverpool had been 2-0 down after an erratic start, which included captain Virgil van Dijk holding up his hands in apology after his wayward header allowed Georges Mikautadze to score the opener for Villarreal.
At Etihad Stadium, Manchester City bounced back from defeat to PSG with a slick 5-1 home win against AEK Athens, with the club's top scorer Erling Haaland on the bench.
Phil Foden scored a hat-trick, with his second goal the pick of the bunch, coming at the end of a sweeping attack.
Atletico Madrid held on with 10 men for a 1-1 draw with Stuttgart, foiling the German underdogs' bid to join PSG and Liverpool on nine points.
Julian Alvarez's goal for Atletico had cancelled out Jamie Leweling's opener when midfielder Morten Hjulman made a reckless sliding tackle from behind on Angelo Stiller to leave Atletico clinging on.
Scott McTominay scored his first two goals of the season to help Napoli beat Bodo/Glimt 4-3 and relieve pressure on coach Massimiliano Allegri.
McTominay, who also hit the post, missed a month of the season after undergoing a surgical procedure in early September to treat an irregular heartbeat.
Serhou Guirassy scored twice, but Borussia Dortmund wasted plenty more chances in a 2-1 win over Azerbaijan's Sabah.
Pavel Kacor's leaping volley in the 90th minute earned Slavia Prague a 2-2 draw with Fenerbahce, who led 2-0 before a defensive blunder by Matteo Guendouzi let the Czech side back into the game.
PSV won 1-0 against Porto, who slumped to a third loss, and Roma cruised to a 4-0 win over Slovan Bratislava.
12°C