The Australian was already in control of Saturday's tour event final against Sally Fitzgibbons at the Keramas break in Bali when she took off on a wave with less than three minutes remaining.

After beginning her ride with a sharp turn near the lip of the wave, Gilmore disappeared as the wave barrelled before emerging unscathed to cheers from the beach.

Her victory, and the world No.1 ranking, was confirmed shortly afterwards when the 10s dropped from the judges.

"I definitely saved the best 'til last," Gilmore told AAP.

"I was just sitting there going 'try your hardest to be on the best wave and get a score. This is the final - you've got nothing to lose'.

"That was when it all came together. The waves were just firing; it's the best feeling in the world when you're competing and the waves are pumping - so cool."

Gilmore's 10 lifted her to a two-wave total of 16.83 out of 20 and left Fitzgibbons (7.00) trailing in her wake.

It's the 12th time in 18 tour meetings between the Australian pair in which Gilmore has emerged victorious.

With Caroline Marks, Malia Manuel, Courtney Conlogue and Carissa Moore all early eliminations, Gilmore's win moves her to the top of the rankings.

It is an exceptional return to form for the 31-year-old who had come into the event on the back of successive quarter-final exits on the Gold Coast and at Bells Beach.

The seven-time world champion was clearly delighted to be back in the leader's yellow jersey, heading into next month's Margaret River Pro in Western Australia.

"I'm stoked. The yellow jersey is pretty important to get your hands on," she said.

"It feels really nice to do that and head on to Margaret River."

The final was an important step for Fitzgibbons, who reached her first tour decider since the 2017 Margaret River Pro.

Her runners-up finish moves her to equal fifth in the standings alongside Bells Beach finalist Manuel.

In the men's competition, Kanoa Igarashi made history by becoming the first Japanese surfer to win a world tour event.

After stopping American legend Kelly Slater's run in the semis, Igarashi was too strong for France's Jeremy Flores in the final.

Australian pair Wade Carmichael and Adrian Buchan were stopped earlier on Saturday in the quarter-finals.

Australian Associated Press