Callum Robson and Molly Picklum are the last Australians standing at the World Surf League's Trestles Pro, both booking quarter-final berths at the California tour stop.
In a mostly disappointing outing for the Aussie brigade, Robson gave his compatriots something to cheer about by upsetting high-flying local hope Griffin Colapinto.
Picklum also advanced to the last eight with a 13.33 to 9.50 victory over Portugal's Yolanda Hopkins.
Ranked 10 spots below world No.6 Colapinto, Robson silenced the San Clemente supporters, delivering a 7.33 on his forehand attack heading into the final moments to clinch a 12.83 to 11.03 win.
"You don’t come up against anyone harder here at Lowers than Griffin. I knew he had the whole community behind him, so I knew I was up against it," said 25-year-old Robson.
"But, for me, I love to draw those match-ups. That’s why I want to be on this Tour because I want to come against the biggest names, and test my surfing and continue to push myself."
Robson, from Evans Head on the NSW far north coast, will take on Yago Dora in the quarters.
Crowned world champion in 2025, the Brazilian regained the No.1 ranking with a victory over French Olympic gold medallist Kauli Vaast.
Jack Robinson, Liam O'Brien and top-ranked Aussie, No.7 Ethan Ewing, were all third-round casualties.
Reigning world champion Picklum, who is currently ranked fourth, will take on American Bella Kenworthy in her quarter-final match-up, with Tyler Wright missing her chance with a loss to Luana Silva.
Carissa Moore almost surrendered her top ranking after giving up priority late in her heat with Costa Rica's Brisa Hennessy.
But the Hawaiian veteran found a late inside gem to take the win and keep second-ranked compatriot Gabriella Moore at bay.
There was more buzzer-beating antics from recent back-to-back Championship Tour victor Erin Brooks, who will face Moore in the quarters.
