Aaron Finch scored a sparkling century against Sri Lanka, setting a new record for the highest score by an Aussie captain at a World Cup, going past Ricky Ponting's unbeaten 140 in the 2003 final against India.
The skipper hit the ball to all parts and scored at a rapid pace, racing to 153 off 132 balls to put the Sri Lankans to the sword.
Steve Smith also showed his class, scoring 73 off 59 as he and Finch put on 173 runs for the second wicket.
But their innings showed up the slow going of David Warner and Usman Khawaja, which could be a problem as Australia go deeper into the tournament.
Sri Lankan legend Kumar Sangakkara praised Finch's knock, especially compared to Warner and Khawaja, who struggled to get away.
"What really impressed me was his mental skills," Sangakkara said. "He had Warner at the other end struggling to not get out and not really focusing on getting runs or reversing pressure.
"Finch kept his innings on a perfect, even keel. (He) saw the new ball out, attacked the right bowlers.
"That's how you get to hundreds — hundreds that matter, hundreds that actually help your side win."
Warner, who remains Australia's second-leading runscorer in this World Cup after he was leapfrogged by Finch, has piled on the runs this tournament but at a slower pace than usual for the aggressive opener.
Australian batting mentor Ricky Ponting said on Friday the "handbrake was off" for Warner after he scored a century against Pakistan.
The left-hander had tallied the two slowest fifties of his career against Afghanistan and India before his ton, and he struggled to get out of first gear against Sri Lanka as he was the first man out for 26 off 48 balls.
Australia have three of the top five runscorers in the tournament in Finch, Warner and Smith. While there is no doubt over Warner's position in the side with 281 runs at 70.25, doubts are growing about Khawaja.
He entered the World Cup as the world's leading scorer in ODIs in 2019 but was shunted down the order from his preferred position of opener. In five matches, Khawaja has hit just 98 runs at 19.50 with a highest score of 42.
Coming in at first drop against Sri Lanka, Khawaja departed for 10 off 20 balls when he went for a slog sweep and hit it straight down the throat of Milinda Siriwardana on the boundary. It leaves him with four scores under 20 for the tournament.
Fox Cricket commentator Brendon Julian said the middle order wobbles are not as noticeable if most of your top order tees off. Fellow caller and ex-Test star Kerry O'Keefe admitted the batting order order is an issue the Aussies won't be able to ignore for long.
"The problem is at three, if it's not Usman, it has to be Shaun Marsh," he said. "I think Shaun Marsh has to bat up the order. I know Steve Smith has been getting runs at three. But I just think if Usman is not to be the player, then Shaun Marsh is lost at five. You've got to push him up.
"You haven't got many problems but if there is a query, it's about who bats first drop."
There is no doubting Khawaja's talent as an opening batsman, where he averages 56.3, but the concerns come with his average of 22.6 in any other position in the order.
Coach Justin Langer backed Khawaja during the week, saying he'll adapt to whatever situation he finds himself in because he's a class player but with Finch and Warner firing at the top of the order with an 80-run stand on Saturday, Khawaja is somewhat in batting limbo.
The Alternative Commentary Collective are podcasting their way through the World Cup. Known for their unconventional sports analysis and off-kilter banter, the ACC have come to ask the tough questions. Here's the latest episode of 'The Agenda':
WARNING: GRAPHIC CONTENT