The Brazil defender has benefited from a change of lifestyle off the pitch, states his manager.
Arteta said: “A lot of things have happened to him. His role in the team has grown. His personal life is also very different to the one he had before with his family and his language.
“He also changed a lot of things in his life and improved his mentality.
"He can decide what he wants to be and I think he made the right call to take the direction he took."