Molly Picklum has become the sole rankings leader of the World Surf League after the Australian youngster moved into the quarter-finals in Portugal, while Hawaiian Carissa Moore was a shock elimination.

The 20-year-old from the NSW Central Coast and five-time world champion Moore shared top spot heading into the Rip Curl Pro Portugal.

But Picklum won her round-of-16 clash on Monday against fellow Australian Isabella Nichols, while Moore fell to local wildcard Yolanda Hopkins.

Picklum posted a convincing two-wave score of 12.17, with her best a 6.50 for a quick barrel ride, however Nichols had a visibly frustrating heat after suffering a broken board and leash at the start and only managed 6.50 overall.

"It was crazy out there," Picklum said.

"It was an early start and I just looked at the ocean and thought I'm going to try and catch as many waves as I can and hopefully one of them will pan out.

"Portugal has been funny, I haven't felt like I got a bunch of momentum at the start, but now I'm feeling good, things are changing and I want to keep putting my time in here because I really want to get to the finals."

She will next take on Portugal defending champion, Brazil's Tatiana Weston-Webb.

In other results, Sally Fitzgibbons scored 8.33 for her two-wave total to score a tight win over fellow Australian veteran and reigning world champion Stephanie Gilmore, who posted 7.86.

Macy Callaghan and Sophie McCulloch will also fly the Australian flag in the quarter-finals.

Competing in her maiden championship tour event after missing the first two of the season through injury, 24-year-old McCulloch upset world No.6 Brisa Hennessy.

After a big wipe-out and a broken board, McCulloch regrouped to lock in a wave for a 5.83 to take the win.

The men's event remained on hold on Monday, up to the round of 16 stage.

Five Australians including rankings leader Jack Robinson will be in action when competition resumes, with the West Australian taking on compatriot Ryan Callinan.