Fiji were looking to make amends after last week's agonising loss to Wales in Bordeaux.
Fiji produced a superb performance to stun Australia 22-15 in their Rugby World Cup clash in Saint-Etienne on Sunday
A week after an agonising loss to Wales when the last pass was spilled with the tryline open, Levani Botia’s teammates had to win to stay in the hunt for their first quarter-final in 16 years.
The Fijians were disciplined, composed and clinical throughout the game en route to their first win against Australia in 69 years.
Australia has brought to the Rugby World Cup its youngest squad in 20 years, a squad still learning how to win. A Fiji side that has been around the block several times gave the two-time champion Wallabies their first Rugby World Cup loss to a Pacific Island team.
This result puts the heat back on Wales and the Wallabies, who meet next Sunday.
Elsewhere, England edged closer to the Rugby World Cup quarter-finals with a 34-12 win over Japan in Nice.
Lewis Ludlam forced his way over from close range for the only try of a scrappy first half before a fortuitous try from captain Courtney Lawes proved to be the turning point.
Freddie Steward and Joe Marchant then made sure of the win but England will need to show more if they are to go all the way
They will next take on Chile on Saturday.