After eight missed cuts in 2025, Grant fired a final-round five-under-par 65 at Bellair's Pelican Golf Club to scorch to a three-shot victory.

Bogey free for 52 consecutive holes, the 26-year-old finished at 19 under for the tournament to pocket $US487,500 ($A746,000) for her second LPGA Tour title. 

American Jennifer Kupcho closed with a 67 to finish runner-up, one stroke ahead of Mexican Gaby Lopez (65) as Australian Grace Kim's quest for a third win of the year faltered on the front nine.

After starting the day in third place, just three shots off the pace, Kim stumbled with two early bogeys before rallying down the stretch to post a 69 and end up equal ninth at 12 under.

As players jostled desperately for spots in this week's $US11 million ($A16.84 million) season-ending Tour Championship, fellow Australian Karis Davidson's final-round 66 wasn't enough.

Only the top 60 in the season-long standings advanced, with Davidson's joint 14th only progressing the 27-year-old up to 74th position.

Tour rookie Cassie Porter also missed out on making the showpiece finale in Naples, in even more heartbreaking fashion.

After starting the week on the bubble in 60th position, Porter dropped to 64th in the points race after a final-round 72 left the 24-year-old Sydneysider equal 56th.

Gabriela Ruffels' joint 28th at six under and Robyn Choi's equal 38th three shots further back were not enough either as world No.5 Minjee Lee was left to spearhead Australia's four-strong challenge at the Tour Championship.  

Even after sitting out this week, Lee is third in the points race behind Thailand's world No.1 Jeeno Thitikul and Japan's British Open champion Miyu Yamashita.

After snaring her maiden major this year at the Evian Championship, Kim (29th), also qualified, along with Hannah Green (38th) and Steph Kyriacou (45th).

Green continued her strong end to the season with a share of 15th at nine under, while Kyriacou also closed with a 67 to tie for 38th. 

Brooke Matthews iced an incredible weekend with a hole in one on the 12th that earned the American a half-million-dollar Lamborghini.

With a second eagle two holes later, Matthews followed up a Saturday 64 with a Sunday 65 to finish tied for eighth and snatch the third-last spot at the Tour Championship from outside the top 60 entering the week.