The 24-year-old netted his first Champions League hat-trick in Tuesday's 5-1 win over Atalanta.
"He is a young English player who has played a lot of games. He is still improving and adding more to his game. He has a striker's nose to get into certain areas.
"He is in the top five players in the world now. Definitely! I don't care who you mention. The effect he is having, the goals he is scoring, it is impossible to keep him out."