Zabaleta is confident that the striker is destined to reach the top.
"Since Mario arrived he has done positive and negative things," Zabaleta told Omnisport.
"He is a player, a person too, who is very difficult to understand because you never know what he is going to come up with next.
"As a player, sometimes not all you have in the feet you have in the head, and Mario is a character that, as a team-mate, sometimes you laugh at what he does and sometimes you want to kill him. But in the end he is a great person.
"As a player he has a great talent. I don't know if he would be fighting for the Ballon d'Or with Messi and Ronaldo but he would be close to being one of the best strikers in the world."