The Catalan giants managed to level their quarter-final tie against Atletico Madrid within 30 minutes thanks to goals from Lamine Yamal and Ferran Torres.
Unfortunately for them, Ademola Lookman managed to pull a goal back in the 31st minute, and it was enough to send Atletico Madrid through.
Speaking to BBC Sport after the game, Flick admitted he was disappointing but has now turned his attention back to La Liga.
"We played a fantastic first half. We had to score more goals. It was really possible. At the end we conceded the goal. In the end, it’s football. But the attitude, I am really proud of that," he said.
"The next step is to win La Liga. We have to show the attitude, the mentality. We are all disappointed. For everyone, it’s a big dream to win the Champions League. Of course we have to learn but we also have a young team. We have to improve and we will improve next season.
"Today, it’s also good to speak about how the players are doing. Every day we have to learn more, we have to be better and this is what we want to do.
"I know it’s very disappointing for everyone but it’s football, it’s life and we have to come back.
"For me, I don’t care about when we win La Liga. I want to win La Liga. It doesn’t matter what day we win La Liga. Now we can focus on La Liga. It’s tough because everyone believed that we could make it happen today but we have to accept it and we will come back."