Fitzgibbons dominated her all-Australian semi-final against Tyler Wright on Tuesday morning, and backed it up in the decider to beat Frenchwoman Johanne Defay 15.24 to 11.23.

The result saw 30-year-old Fitzgibbons rise from sixth to second in the rankings, putting her in a good position to finish in the top five and qualify for the new-look WSL title decider at the end of the year.

Fitzgibbons is a three-time runner-up in the Championship race, and she would love nothing more than to break through for a long-sought maiden world title.

"I was writing those goals that I need to win an event to even have a shot," Fitzgibbons told AAP about her hopes of qualifying for the world title event at the end of the year.

"Every day I'm looking at the things I want to achieve. I was on the bus in the dark this morning, and I thought 'yep, it's totally possible to win today'."

Wright, who opted against a warm-up surf before the semi-final, struggled for fluency throughout the heat and fell over a remarkable seven times.

The 27-year-old two-time world champion could only manage a two-wave total of 7.64, far short of Fitzgibbons' 15.43.

Defay upset four-time world champion and current world No.1 Carissa Moore in the other semi-final, but fell short of Fitzgibbons in the decider.

Fitzgibbons, who hails from Gerroa in NSW, felt the conditions at Rottnest suited her.

"To wake up and there's so much energy in the swell, it was such a pleasure to be out there and try to crack the code," she told the WSL broadcast.

"It's got a few similarities to a bunch of different waves at home. So I kept telling myself 'oh, there's a section out front of my house'.

"And I try to accelerate off the bottom and trust my instincts. On a few of them there's some pretty crazy ends."

Moore entered her semi-final as a hot favourite to progress, and boasting a 7-1 head-to-head record against Defay.

But it was Defay who set the early pace, and her late 8.83 wave secured the win 13.50 to 12.83.

Australian Associated Press