Ko roared home with a final-round seven-under-par 65 to storm to a four-stroke victory over American Andrea Lee (69) after finishing 21-under for the tournament.

The resurgent former World No.1 bagged eight birdies to leave the field in her wake, with Koreans Hye-Jin Choi (68) and Hyo-Joo Kim (68) and American Lilia Vu (69) sharing third at 16-under.

Lee entered the third-last event of the LPGA Tour season with a 29-point advantage over Ko in the player-of-the-year standings.

But Ko has nudged a point ahead of the West Australian after collecting 30 points for her second win of the year.

“I feel so proud to be born in Korea. I think because of that I really wanted to win here. It's not only just a place that I'm born, but a lot of my family is still here,” Ko said of her Korean heritage after the win.

“This week my relatives are here, my direct family is here. And I wanted to win it for them as well. To be able to do that this year in front of a lot of them, it means a lot.”

With only the top-10 finishers earning player-of-the-year points, Lee received nothing for tying for 51st at one-under after closing with a 71.

“I feel so proud to be born in Korea. I think because of that I really wanted to win here ... To be able to do that this year in front of a lot of them, it means a lot.” - Lydia Ko.

Hannah Green (69) was the best-placed Australian, sharing 10th at 10-under for her sixth top-10 of the year.

Steph Kyriacou (74) was equal 19th at seven-under.

Thai teenager Atthaya Thitikul entered the final round with a one-shot lead and would have vaulted to the top of the player-of-the-year standings had she won.

Instead, Thitikul disappointed with a two-over 74 on Sunday to settle for outright sixth, a distant eight shots adrift of Ko.

The 19-year-old rookie-of-the-year shoe-in still made up some ground with two events remaining before all the awards are decided.

Players pick up 30 points for a tournament win, 12 for second, nine for third and so forth down to one point for finishing 10th.

The second-ranked Thitikul, third-ranked Lee and fourth-ranked Ko also remain in the hunt to usurp Jin Young Ko as World No.1 by year's end.

Whatever transpires, Lee has already secured the Annika Major Award as the season's best-performed player in golf's four women's majors after winning the US Women’s Open and finishing joint runner-up at the KPMG Women’s PGA Championship.