Hansi Flick claimed Paris Saint-Germain are simply a better team than Barcelona, who will take lessons from their Champions League defeat.
Tuesday's contest between two of Europe's best teams served up a thriller at the Parc des Princes, where PSG won 4-2.
Barca twice dragged themselves level, through Xavi Espart and Lamine Yamal, but Vitinha and Fabian Ruiz clinched the points for PSG late on.
PSG had 22 shots, with Barca having 18. Blaugrana goalkeeper Joan Garcia made 10 saves, while the hosts recorded 3.7 expected goals to the visitors' 2.23 xG.
And Flick felt, ultimately, two-time reigning European champions PSG are just a better side than his Barca team, though he is sure the Blaugrana will have learned plenty.
"It was a fantastic match, from both teams. PSG showed they are a better team than us," said Flick, who is one win shy of picking up his 100th for Barca.
"We lost, but we learned. Mistakes happen. But what we've done in recent weeks is fantastic.
"Today wasn't easy; the players ran a lot and tried to play. What happened after Sevilla, with the recovery, wasn't the best. It's not an excuse.
"We have to learn. It's October, and you don't win titles in October; the Champions League is won in June."
Barcelona have scored 50 goals in just 12 games in all competitions this season.
However, PSG had 15 shots on target, the most Barca faced on record (since 2003-04) in a Champions League match.
Flick, though, believes that was down to PSG's attacking quality, and not necessarily because Barca defended poorly.
"I think PSG also scored a lot of goals against City. In the end, in the last 10 minutes, the team dropped off, and we conceded the fourth," Flick added.
"But I saw some very good things. We have potential. I'm not negative. It was a good experience. We have to do better."
Barca will now turn their focus back to LaLiga, and Sunday's upcoming Clasico.
Should the Blaugrana beat Real Madrid, they will become the first team to win their opening 10 LaLiga games of a season.
Midacksy
8
Hansi flick, you have done well so far for the club. It's true Psg we're better than us but the failures of the team for the past seasons has been the same. Our defense is not good at all we have to admit that but you are the coach and you made the decision not to bring in an experienced center half defender, last season we did not keep a single clean sheet in the champions league and so far its also going the same route 3 games and goals conceded in all. We have to also be realistic with our transfer business, why renew Christensen knowing his never fit instead of letting him go and bringing a fit center half. We as fans and supporters of FCB should be humble and realistic. We are not defeating BIG TEAMS in the champions league so how do you win? We have to be realistic plus the tactical set up in those games. Rafinha a captain thinking about the El clasico in a disturbing defeat like this, is purely a low mentality whether we like it or not. However, if we keep thinking we are that good while losing to big teams in Europe when in matters then am sorry for our heart breaks.