Barca were impressive as they won Wednesday night's Champions League tie 3-2 in Dortmund.
Casado later said: "We knew it was a difficult pitch and they got back on track with the draw. It was an intense second half, but we knew how to play our cards.
"We have taken the three points and are taking a step towards qualifying.
"The last few games in the League have not gone as we wanted, but in the Champions League things are going well.
"We controlled the ball in the first half, but in the second we were more effective. They tied the game, but the team was able to react."
On teammate Pedri, he also said: "Pedri is a world-class player. When I have problems, I always give it to him. It's a guarantee to play alongside him."
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