However, the ex-Turkey international says Guler must push himself more.
He told Radio Marca: "We have to wait for him to become a world star. He is on the right path, he is progressing. But he lacks some things to be a star. But he has time, he is still young.
"He is showing quality, he has an impressive foot. But today there are many more things that are important during the match and he still has to improve there."
Korkut continued: "I see it as a coach. We saw it during the last game, that he played up front without defensive duties. If he wants to play for Real Madrid as a starter he has to demand more of himself, above all to cover more metres.
"He is playing in a few metres and in those few metres he is playing impressively, with maturity and an impressive technical level. But to make a place for himself you also have to run and that is what he lacks. There is no better place to learn than at Real Madrid because they demand more of you."