Yamal, 16, signed a new deal with Barca this week.
Xavi said, "I talk to him a lot. He is an involved player, he tells me what he sees.
"The summary is that he is happy, happy, he benefits a position where he can enhance his talent, he looks out for the team, and all his talent comes out. He is supportive, generous and that is why things are going for him.
"We have expert players and very young ones, like Balde, Gavi, Lamine ... and this mix makes the team flow. The experience and self-confidence and dynamism of young people matter. And hopefully Lamine marks an era, but we are not doing him a favor by talking about him and comparising him with Messi."