Teenager Jordan Petaia has starred on debut for the ill-disciplined Wallabies, who came alive in the second half to dispatch Uruguay 45-10 at the Rugby World Cup.
Winger Dane Haylett-Petty and outside centre Tevita Kuridrani both bagged doubles while winger Petaia crossed with his second touch as Australia ran in seven tries to one in humid conditions in Oita on Saturday.
The performance was marred by first-half yellow cards shown to forwards Adam Coleman and Lukhan Salakaia-Loto, both for high tackles.
Other Australian high shots were also penalised in a concerning lack of discipline from Michael Cheika's team, who were punished by match officials for similar offences in the opening win over Fiji and the loss to Wales.
A 12-5 penalty count against them is a headache Cheika must address ahead of Friday's final pool clash with Georgia.
The bonus point win means Australia have virtually locked down a quarter-final berth, with only a series of upsets able to deny them.
The remain on track to finish second in pool D but could yet claim top spot if Fiji upset Wales in Oita on Wednesday.
Petaia was the brightest element to emerge from Australia's biggest Test win since thumping the same opponents 65-3 at the last World Cup four years ago.
The 19-year-old had limited opportunities but displayed a good work effort to secure his try and backed that up with a thrilling assist to Kuridrani in which he slid past three defenders and threw a memorable assist.
Australia's youngest player at World Cup, Petaia made way at halftime in a pre-planned substitution.
The Wallabies went to another gear in the second spell, crossing four times against the 18th-ranked South Americans, who nevertheless had the final say through a try to No.8 Manuel Diana.
Australia made their best start of the tournament setting up Haylett-Petty before their discipline turned south.
French referee Mathieu Raynal brandished his first yellow card when deeming Coleman had tackled fullback Rodrigo Silva around the shoulder.
That 14th minute infringement was followed 15 minutes later by a near-identical indiscretion from flanker Salakaia-Loto.
Neither incident looked bad enough to earn a citing but both players will be nervous after lazy efforts.
Australia notched a solitary try during both periods with 14 men, with Petaia at the heart of each.
Up 19-3 at the break Australia dominated the second spell through power runners such as man of the match Kuridrani, flanker Jack Dempsey and reserve prop Taniela Tupou. All three were making their first appearances of the tournament.
Kuridrani, Will Genia, James Slipper and Haylett-Petty were the second-half try-scorers.
Slipper's try was greeted with delight by teammates, with the veteran prop having failed to score in his previous 93 Tests.
