The youngster was impressive in midfield for the 3-0 win.
Koeman said, "Pedri is a player who is very good from a more focused position.
"The connection with Leo (Messi) and others is good. He's playing well, he's working hard.
"Without the ball he is important in our team, it seems that he is comfortable in his game. But I think other players should also be highlighted."
On Miralem Pjanic, Koeman added: "He has played well. He has had to wait for his chance for an entire match. We have competition in midfield. He played a great game today, he was important between the lines. Defensively he was good."