The 19-year-old is already a regular for his club and his country, and Mata says that it is remarkable to see that kind of consistency at such a young age.
As reported by ESPN, Mata said: "I think he has been brilliant. I think he is a special kid. He has a lot of talents and he has got a good mentality which is important at that age.
"He is performing very well, week in week out – even coming from the bench he is helping a lot.
"I really believe he is going to be a big player for club and country. I see so many players at that age and they don't keep consistency, but I believe he can because he has the right mentality for that."