The pair didn't see eye-to-eye when together at City.
But Yaya says: “Pep came and improved him and Aguero. De Bruyne. Walker who was already a good player became different class.
"For players like that, as a manager Pep is fantastic."
He added: “He is a top manager. Pep is the type of guy who can take a talent and get it to its maximum level."