Yamal will soon return to Barca for preseason a Euros winner, having been named the best young player of the tournament.
Ter Stegen said: "Xavi gave him the opportunity to compete in all the games. Then it is true that Lamine has something special. We have seen it in the team and it has also been seen in the Euro Cup . He is a different player and he still has room to continue improving because he is a footballer who makes a difference.
"I hope he continues with his feet on the ground, because I have already heard that he has a great future and more... For him, it has to be important to concentrate on the moment and enjoy it, but keep working for the team as he has done so far.
"In the end what matters is the mentality; being prepared in every game, giving 100 percent. This is what he has to do, work for the team and improve all aspects because he is still very, very young and this is just beginning for him."