Speaking to Soccernews in collaboration with Tipsbladet, Stam said: "He has made a really good impression on me. I think he is a really good player. He is very talented. He has an excellent left leg, a really good physique and lots of speed. And he has shown that in his first matches for United.
"The thing about him, when he comes to such a big club as a very young man, is that it is not easy for him to show his qualities. Because he also needs the players around him. He needs them to put him on stage and give him opportunities to score. He plays in a team that lacks confidence. He has players around him who don't have the confidence and maybe not even the qualities to play at this level. So it's not going to be easy for him, but he's just going to have to do what he can. He must show his qualities and work hard. Hopefully, he scores some goals and then he gets even more confidence."