Chelsea midfielder Hakim Ziyech says former Ajax teammate Donny van de Beek will prove himself at Manchester United.
Van de Beek has had a difficult start to his Old Trafford career.
But Ziyech says: "I spoke to him when he moved to Manchester, but in the last week we didn't speak a lot and we didn't speak about his situation.
"When you come from a different country and there is a different style of play, I know for sure it will take some time for him to get used to.
"He will bring his quality to the squad and it's most important for now to stay calm."
