"For me, he can be one of the most exciting talents in world football. I genuinely believe that.
"You see a lot of good players, but this kid - for 19 years of age - he burst onto the scene at the World Cup, but we'd tracked him before that, we'd seen him as a young player playing in the youth internationals. He has everything to be world class.
"He's super fast, has a wonderful touch, he's a good size and is aggressive. What I like, and what I have in other players, is that humility to work hard.
"I've seen enough of him over the course of the last couple of seasons to think this is a kid who, coming into the right environment, can genuinely be world class.
"He will go back to Lille and play there for the season on loan, but by signing him, we'll have a wonderful player - not only now when he comes in next season, but also in the future.
"He can light up world football, for sure."