Barca won 5-1 via goals from Gavi, Jules Kounde, Raphinha, Ferran Torres and Lamine Yamal.
Flick later expressed his satisfaction with the performance of his young team.
The match:
"Today was an important victory after beating Real Madrid. We saw what the team can do. We travelled, we didn't train on Monday, we only trained yesterday. The performance was good from the start. We controlled the game."
Dani Olmo, false nine:
"Dani knows very well how to play as a 9. He has played there in the national team. I spoke to him. Lewy was not an option, I gave him time to recover. The plan was good. We made a good strategy, we controlled the ball, the distance between the players was good..."
Pedri:
"He's everywhere. He understands football. He knows how to combine. It's nice to watch him. He performs in every game. When we look at the data, we see that he runs a lot and does fantastic things with the ball. It's important for him to improve. His development is important. We need someone who controls the game."
Ronald Araujo:
"He has a one-and-a-half-year contract. I had no doubts. I'm happy that he's here. We'll see what the future holds for him. He's performing well, he did it again today. The defenders and the team have noticed his return."
Gavi:
"I like the way he presses. He knows how to control. He's dynamic, along with Raphinha. He's everywhere. He knows how to do his job. He's very important in defence and in attack. He knows how to play with the ball. I'm very happy with him."
Fans:
"I hope they enjoy it. When I saw the light of the mobile phones raised, I enjoyed it. There was a great atmosphere. The players performed well, and if they gave their all, the fans were there. There was a connection. It was very good to see.
"The idea is to continue our run in LaLiga. We will try. We always take things step by step, game by game. We want to play and win."
Lewandowski:
"If Szczesny doesn't play, he won't either. No, I'm joking. He had to rest."