Australia is top of Group C ahead Egypt and Spain, who drew 0-0 in the other game
Two-time Olympic men's football champion Argentina was stunned 2-0 by Australia in their opening game at the Tokyo Games on Thursday. (More Sports News)
In its first Olympic game since 2008, Australia took the lead through Lachlan Wales' tap-in the 14th minute at the Sapporo Dome.
Marco Tilio secured the victory in the 80th, just a minute after coming off the bench.
Australia is top of Group C ahead Egypt and Spain, who drew 0-0 in the other game.
The Argentines won Olympic gold in 2004 and 2008. Australia's best showing was fourth place in 1992. (AP)