Benitez said: “I don’t have any doubts about him because he has the quality and the intelligence.”
He added: “When West Ham got Tevez and Javier we knew it would be difficult for them.
“Players need time to settle and if you don’t talk English it makes it even tougher. But I think his experience at West Ham will help him settle in quicker here.
“The Premier League can be difficult for some people but I don’t think so with Javier. It will help that we can speak Spanish to him.
“He will add a lot of balance to the team. He is only 22, but already has 22 caps for Argentina. How many English players of that age have played for the national team so many times?”