PARIS -- Barcelona coach Hansi Flick said his tired side made too many mistakes as their perfect start to the season ended with a 4-2 defeat to Paris Saint-Germain on Wednesday in the Champions League.

Desiré Doué, Lucas Hernández, Vitinha and Fabián Ruiz were all on target as PSG edged an enthralling game at the Parc des Princes to make it three wins from three in Europe this season.

Xavi Espart and Lamine Yamal had twice drawn Barça level before the Spanish champions conceded twice late on as their 11-game winning run at the start of the new campaign came to an end.

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"I think it was a fantastic game from both teams," Flick said in the post-game news conference. "We made too many mistakes, especially in ball possession, easy ball losses.

"This is what we have to analyse. But I saw a lot of good things also. For me it was a great test for us. You saw today in which areas we have to improve. This is what we will do.

"We have to understand the mistakes happen because [the players] are not fresh. What they had to do the last couple of weeks is unbelievable. I appreciate the attitude. A lot of things were fantastic."

The fixture had been billed as a clash between the best two sides in the world right now: back-to-back European champions PSG taking on a Barça side that had scored 48 goals in their 11 wins this season.

Barcelona's 11-game winning start to the season in all competitions had been tied for the third-longest winning start by a team from Europe's top five leagues and tied for the longest by a Spanish club.

However, Flick lamented Barça's preparation for the match, with their flight back from Seville after beating Real Betis on Saturday cancelled due to storms in Spain.

"Everyone knows what happens after [the Betis win], so it's not the perfect recovery," he added. "It's not an excuse, just for you to understand why maybe we were not at the top level.

"But it was a good level. We have to learn from this game. PSG had a lot of chances -- Joan García was fantastic in goal for us -- but so did we. We have to take them. This is what I saw from PSG today.

"But in October you can't win titles. You win the Champions League in June. This is the way how we want to do it."

Flick also confirmed the surprise decision to start Rodri on the bench was made with Sunday's visit from Real Madrid LaLiga in mind.

Victory in the Clásico at Spotify Camp Nou would move Barça nine points clear of José Mourinho's side and extend their winning streak in the league to 10 games.

"Yes," Flick said when asked if Rodri, who came on for the final 30 minutes, was reserved for Madrid. "He played a lot of minutes with [Spain] and also the last games with us after the break.

"I spoke with him and told him we make this decision and [Marc] Bernal started. For me, it was a good solution. Hopefully he's fresh on Sunday."

Dani Olmo could miss the Clásico, though. The midfielder was substituted in the first half and will undergo tests back in Barcelona on Wednesday.

"He is very disappointed," Flick said. "We don't know yet how big the injury is. We have to wait and see."

PSG coach Luis Enrique agreed with Flick's assessment that it was a fantastic game, praising the effort his team put in defensively against the "best possible" opposition they could have faced.

"What I loved is how the players were capable of playing a sensational first half defensively, winning a lot of balls with the high press and creating chances to score more goals," Luis Enrique said.

"And then we overcame difficult moments in the second half when Barça had 15 minutes when they dominated and were better. But we are a team that adapts to whatever happens on the pitch.

"I think we played aggressively, strong ... You can see how difficult it is to press players of this level: Pedri, Lamine, Olmo, Raphinha, [Anthony] Gordon, Espart, [Pau] Cubarsi. They are talented as individuals and as a team. This is the best level we could come up against."

ESPN Research contributed to this report.