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Substitute Goncalo Ramos bagged the winner in the 90th minute for the holder, which had fallen behind early on before taking control of the match.

It was PSG's third consecutive triumph over Barcelona away from home and maintained its perfect start to the UEFA Champions League campaign, after it opened with a 4-0 win over Atalanta.

Barcelona, lifted by the return of 18-year-old Lamine Yamal, started well.

The Ballon d'Or runner-up, who had missed his side's opening win at Newcastle United, sparkled from the get-go, showcasing his ability in the second minute with a mazy dribble and cross that Ferran Torres failed to convert.

Yet Barca's pressure paid off in the 19th minute when Marcus Rashford delivered a precise pass across the box to Torres, who slid in to beat the offside trap and slot past PSG goalkeeper Lucas Chevalier.

PSG, however, responded tenaciously despite missing captain Marquinhos and its starting attacking trio of Ousmane Dembele, Khvicha Kvaratskhelia and Desire Doue in addition to midfielder Joao Neves, who was injured during the warm-up.

It took control of proceedings and Barca keeper Wojciech Szczesny made a fine save to palm round the post a venomous free kick by Achraf Hakimi from the edge of the box that was destined for the top-right corner.

PSG equalised in the 38th minute when Nuno Mendes embarked on a dazzling run down the left, beating three defenders before setting up 19-year-old Senny Mayulu, who finished clinically into the bottom corner.

Bradley Barcola wasted a great chance to give his side the lead in the 42nd minute, running past Eric Garcia inside the box but blasting his effort well over the crossbar.

PSG was a constant threat in the second half as Barcelona's defence struggled to contain the French side's speed in the channels.

Ibrahim Mbaye almost scored with a strike from inside the box in the 50th minute and Szczesny made a stunning save to block a Barcola effort from close-range two minutes later.

Barca, however, had a great chance in the 62nd minute when Hakimi made a crucial goalline clearance to deny a Dani Olmo effort that had already beaten the goalkeeper.

But PSG got the breakthrough late on. After substitute Lee Kang-in hit the post with a shot from the edge of the box in the 83rd minute, it finally scored a deserved winner from a quick counter in the 90th, with Hakimi crossing for Ramos to fire home from close range.

"It was a close match, but we still believed in ourselves despite facing a lot of injuries. Those who played were top notch," PSG defender Mendes said.

"That's what we need, players who come in and help us when needed, playing our style of football. We showed our work at the top level.

"We know that this year it's going to be more difficult because everyone wants to beat us. We know that and we're focused. We always come to win."

Barcelona will host Olympiacos in its next group-stage match on 22 October (AEST), when PSG travels to Bayer Leverkusen.