Lionel Messi was the star of the show for Argentina with two goals with Manchester City striker Sergio Aguero netting the other.
The win leaves Argentina on 17 points from eight maches and on course to reach the finals in Brazil
A brace by Atletico Madrid striker Radamel Falcao led Colombia to a 2-0 home victory over Paraguay as they kept up their pursuit of Argentina.
After a goalless first half, Falcao scored in the 52nd and 88th minutes to seal their third consecutive qualifying win and leave Paraguay rock bottom of the group.
Alongside Colombia on 16 points are Ecuador, who came from behind to beat Chile 3-1 at home.
The star of the game was Lokomotiv Moscow's Felipe Caicedo, who scored in the 32nd and 55th minutes, while Segundo Castillo completed the scoring for the hosts in the injury time.
It had not looked so easy in Quito when Juan Paredes Reascos sent the ball into his own goal in the 24th minute, but Chile could not maintain their rhythm and had Pablo Contreras and Juventus' Arturo Vidal sent off.
Finally, in La Paz, Bolivia and Peru drew 1-1, Juan Carlos Marino putting the visitors ahead in the first half and Alejandro Chumacero levelling shortly after the break.