A fired-up Sally Fitzgibbons has shown her World Surf League rivals she's far from done, blitzing her elimination heat at the Margaret River Pro.

Fitzgibbons was facing a third straight year of heartbreak, with the veteran's Championship Tour season over if she bowed out in the sudden-death round on Monday.

With the women's field cut to just 10 surfers following the round five event - and only four spots still up for grabs - Fitzgibbons effectively needs to make the semi-finals to move up from 14th and guarantee a start in the remaining 2024 events.

In 2022 Fitzgibbons missed the mark but received a wildcard for the remaining three events, while last year she had to compete in the Challenger Series to re-qualify for the elite level.

Fitzgibbons got off to a nervous start in her do-or-die affair against fellow Australian Bronte Macaulay and France's current world No.2 Johanne Defay on Monday.

Holding down second spot behind Defay with 11 minutes remaining, the 33-year-old boldly took to the air but wasn't unable to stick her rotation.

But Fitzgibbons then landed one of the manoeuvres of the season with a radical layback snap, the big hanger earning a score of 8.17 to take the lead.

She punched the air with delight at landing the move.

The 2027 Margaret River champion followed up with a 8.10 ride for a dominant win at 16.27 over Defay (13.73) while trials winner Macaulay lost her second wave score due to interference.

"This is so fun," a beaming Fitzgibbons told the WSL.

"That's the stuff you dream up, the last 20 years, that gets me out of bed.

"You think you want to try this stuff in pressure moments ... just so much adrenaline, but they're the moments, that's why I keep playing the game and just keep fighting for my surfing because if I fight for another opportunity hopefully I can keep showing a bit more."

Fitzgibbons will meet defending world champion, American Caroline Marks in the next round.

In the men's opening round on Monday, Australia's big guns Ethan Ewing and Jack Robinson moved straight through to round three.

Current world No.2 Ewing posted the highest wave score of the day, nailing a 9.5 en route to a total of 17.00 in his victory over American Kade Matson (15.00) and fellow Australian Reef Heazlewood (12.30)

Local hope Robinson, ranked world No.5, finished second in his heat after scoring 14.66, behind three-time world champion Gabriel Medina (15.00), with Brazil's Deivid Silva (12.83) third.

Currently ranked world No.21, defending Margaret River Pro champion Medina needs to maintain his spot with the men's field reduced to 22 in the mid-season cut following this competition.

Ewing and Robinson are already safe while fellow Aussies Liam O'Brien and Ryan Callinan are also inside the cut pending results from this event.

Among other results, Australian wildcard George Pittar and West Australian Jacob Willcox were heat winners.

Callinan and O'Brien also advanced while Callum Robson won his elimination round late Monday before surfing was called off for the day.

Legendary American Kelly Slater, 52, will have to surf his way through the elimination round after finishing third in his heat.

It could be the last-ever Championship Tour event for the 11-time world champion, who needs victory at Margaret River to make the mid-season cut and has already flagged his retirement.