Molly Picklum's title defence at Hawaii's Sunset Beach remains on track with the young Australian continuing her strong start to the World Surf League season.
A finalist at the nearby Pipe Pro last week, earning the first ever perfect score of 10.00 by a woman at the famous North Shore break, Picklum booked a quarter-final berth at Sunset as the women's event finally got under way on Tuesday (Wednesday AEDT).
She was joined in the last eight by Isabella Nichols, while the Australian men who will be in action on finals day on Wednesday (Thursday AEDT) are Jack Robinson, Liam O'Brien and Ryan Callinan - also at the quarter-final stage.
World No.2 Picklum had a slow start against Victoria's India Robinson with an early error, throwing away priority, but the 21-year-old found her groove as the waves rolled through.
She posted a 7.50 and in the dying seconds a 7.17 on her way to an impressive total of 14.67 to best Robinson's 11.00.
"I tried to stay patient and when there were some waves I rolled the dice," said the NSW surfer, who will next take on American Lakey Peterson.
"I'm happy that I got a nice wave to do some turns."
The Paris Olympian said being defending champion added to her belief about what she could achieve at Sunset.
"(It) just adds another story in your brain. It's not pressure but just more noise in your head," Picklum said.
"It's all good - it means that I can surf this wave and I have the ability to take it out, so let's do it again."
Nichols upset two-time world champion Tyler Wright in another all-Australian round-of-16 clash.
In a see-sawing battle, the 26-year-old Queenslander produced the best score in the heat - 7.33 for a deep turn on a big section - to edge Wright with a two-wave score of 14.10 to 13.27.
"I watched it back and thought, 'Oh my god that was actually a really big wave'," Nichols said.
"If I didn't land that I was snapping some ankles, so I was stoked I landed it and with the score I got too.
"I knew Tyler was going to be a really tough opponent because (of) her open face carves ... growing up watching her on waves like this, I tried to surf like her."
Nichols next faces local star Bettylou Sakura Johnson, who scored 11.40 to eliminate Australian veteran Sally Fitzgibbons (10.73) in the round of 16.
Pipe winner and rankings leader Caitlin Simmers remains in contention, scraping through in a low-scoring heat against fellow American Sawyer Lindblad.