Fitzgibbons won by the wafer-thin margin of 14.10 to 14.03 in a close final against Hawaiian opponent Coco Ho on one-to-three foot waves.
The lead switched between one surfer and the other time and again before Fitzgibbons found a blowing left-hander to swing the final her way right at the death.
"That was so crazy and Coco (Ho) had me on the ropes for sure," Fitzgibbons said. "I just had my fingers crossed and knew there would be one towards the end. I made a few mistakes and it happens in Finals but I was able to recover there at the end. I’m so excited."
"This result really opens things up for me,” Ho said. "I’ve been having a really tough year and I’m stoked to get into this Final. This is my best result of the year and this has been an important event for me. Congrats to Sally on her win."
RIO PRO FINAL
1 - Sally Fitzgibbons (AUS) 14.10
2 - Coco Ho (HAW) 14.03
RIO PRO SEMI-FINALS
SF 1: Coco Ho (HAW) 14.16 def. Alessa Quizon (HAW) 10.94
SF 2: Sally Fitzgibbons (AUS) 15.47 def. Carissa Moore (HAW) 15.36
ASP WOMEN’S WCT TOP 5 (After Billabong Rio Pro)
1. Stephanie Gilmore (AUS) 38,400 pts
2. Sally Fitzgibbons (AUS) 36,900 pts
3. Carissa Moore (HAW) 30,200 pts
4. Courtney Conlogue (USA) 29,600 pts
5. Tyler Wright (AUS) 28,700 pts