Koeman stressed that he was happy with Fati's display despite the youngster not having contributed much in the Clasico.
"[Ansu Fati] played his game," said Koeman.
"He worked to help the team. He had a chance in the first half, but they defended well. I think the discomfort he feels has nothing to do with his knee. I don't think it's serious.
"He played 70 minutes and it is a lot for him, and he has to rest to be fine against Rayo [Vallecano]."
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