Barca won 2-0 in Jeddah via goals from Gavi and Lamine Yamal on Wednesday night.
Afterwards, Flick was immediately asked about the registrations of Pau Victor and Dani Olmo now being settled.
He said, “I am very happy for both of them and for the team. We met them on the bus and the whole club is very happy with the decision.
“The players are happy. For us it was a good sign before the game. We wanted to show that we are a team.”
On the win, Flick also said: “We made a great start, but we are a young team and we have to learn things. But this is the way to play. We played very well against Atlético and it was not the best way to end the year, but we played very well against Barbastro and today against Athletic, keeping a clean sheet.
“We are a young team and they can learn a lot. But they know how to play and how to enjoy football. This is the path we want to show in the upcoming matches.”