Centre forward Gonzalo Higuain (50th, 86th minutes) struck twice while Ezequiel Lavezzi c(3rd) and Lionel Messi (32nd) also found the target for the 14-time Copa America champions. Higuain is now the highest scorer in the tournament with four goals in five matches.
Argentina are gunning for their first major trophy since 1993 when they won their last Copa America title. They will meet Columbia or Chile in the final on Sunday.
Wednesday’s match also saw Messi create history as he became the highest ever scorer for Argentina. He is now on 54 international goals, overhauling the previous record by former star striker Gabriel Batistuta.
There was a worrying moment for Argentina however, as Lavezzi injured himself after falling over the advertising boards while attempting to head the ball.
The Paris Saint-Germain winger had to be stretchered off and faces a battle to be fit in time for the final.