NSW surfer Fitzgibbons sealed victory in four-to-five foot (one-and-a-half metre) waves at the iconic Australian break after an uncharacteristic mistake from Gilmore mid-way through the 40-minute final.
“I’m speechless,” Fitzgibbons said. “I’m so pumped. That was tough. Bells went to sleep on both of us and it got real tactical at the end.
“Steph only needed a small score and I just hung on for dear life.
"That wave she took at the end looked so small and I had a feeling there was going to be another set, but there wasn’t.
"I just can’t believe I won Bells two years in a row!”
The 24-year-old Gilmore had been in scintillating form all day beating Hawaiian Malia Manuel in the quarter-finals before displaying huge amounts of confidence in waiting for the very last wave of the heat to defeat NSW teenager Tyler Wright in the last four.
The Queenslander won both match-ups with single wave scores of 9.77 points.
But the Gold Coast native, who struggled in 2011 after suffering a brutal attack at the hands of an intruder at her home in December 2010, fell off the best wave of the final and was unable to repeat her semi-final trick in snatching a late win.
“I’m a little bit tired but feeling good,” Gilmore said. “I felt like I was surfing pretty well and knew it was going to be a hard road.
“I thought I was consistently putting things together and surfing well and then I came up against a brick wall in Sally. It was a good final and Sally deserved this win and she’s great for women’s surfing. Congrats to her.”
Fitzgibbons beat American rookie Lakey Peterson in her quarter-final on Saturday morning before downing reigning world champion Carissa Moore in the last four.
The 21-year-old’s single wave score of 7.33 was enough to wrap up the win after Gilmore could only manage a 6.5 on a smaller wave before failing to find a suitable wave in the final sets to snatch victory from her compatriot.
Despite having priority on the final set of waves, Fitzgibbons opted to pass leaving Gilmore free to go for a last-gasp score that could have seen her steal the win.
The previously free-scoring Gilmore caught the wave but failed to pick up the relatively small score she needed to emerge as victor.
"I thought 'oh, crap - I think I just let this go'," Fitzgibbons said.
"But I thought it was flat. That was the mindset I had and thankfully, that's how it turned out.
"It was such a tactical and tough battle. Steph had been dropping high scores and I'd been dropping high scores all day.
"But with the tide rushing in, it became who could adapt quicker and find that gem among all those failing waves."