Ricardo Alvarez scored the first and Lionel Messi added the second off the bench as coach Alex Sabella chose to give breaks to a number of his leading stars.
Sabella chose not to risk the likes of Messi, Sergio Aguero, Gonzalo Higuain and Angel di Maria from the off and the decision did not cost him.
Alvarez quickly put Argentina ahead when, in the 11th minute, he scored from the edge of the box. Most were expecting him to pass but he took on the strike and found the net.
Maxi Rodriquez then had a chance with a long-ranger, before the same man hit the post.
Sabella made changes in the second half and sent on the likes of Messi and, after that, the Barcelona man took control. He put in Di Maria who in turn crossed to Aguero. The Manchester City man flicked a header to Messi and he wrapped things up.
"We have a great group and team, a World Cup is very tough and we will have to fight a lot for it," Messi said.
"We arrive with the right age, with most of us playing in the best leagues of Europe for years. Winning it is our target, but it will be very hard."