Two-time Surfest champions Coco Ho and Sally Fitzgibbons stood tall to make the final 16 in the Holmes Civil Developments Pro at Merewether on Friday.
Ho, the defending champion, and world No.6 Fitzgibbons won their round three and four heats in choppy, one-metre conditions.
The pair are vying to join Rebecca Woods and Pam Burridge as the only three-time winners of the women's contest.
Ho, who beat two-time world champion Tyler Wright in the 2018 final, thrived in the testing conditions and faces Kiwi Paige Hareb on Saturday in the 6000-point qualifying series event.
"I was super stoked to get to surf off the rocks," the Hawaiian said. "It's a perfect little right and I feel like I'm designed for that, but I was stoked to get on the open face. It was very stressful, it wasn't that easy. Everyone is getting scores and you don't know how it's going to pan out."
Fitzgibbons was last and needing a 5.38 late in her round four heat and earned a 6.47 to win. She faces another Australian championship tour surfer, Nikki Van Dijk, in round five.
Merewether's Philippa Anderson, the 2009 champion, bowed out in round three. The 27-year-old started with a 3.77 and backed it up with a 4.03 with seven minutes left in the 25-minute, four-woman heat. She needed a 5.44 late but there was little on offer and she finished last. Port Stephens wildcard Elle Clayton-Brown was also eliminated.
Top seed Tatiana Weston-Webb, Macy Callaghan and Johanne Defay were among the major casualties.