Defending champion Kim Sei-young of South Korea held a one-shot lead over compatriot and world number one Ko Jin-young after the third round of the LPGA's season-ending CME Group Tour Championship in Naples, Florida, on Saturday.
Kim, who carded six birdies through her first 13 holes and was blemish-free on the day until a bogey at last, shot a five-under-par 67 that brought her to 13 under on the week at Tiburon Golf Club.
If Kim, who also led last year's season finale after 54 holes, can close out the win it would be the first time she has successfully defended a title and make her the only three-time winner of the 2020 campaign.
"Really good chance to chase everything," said Kim. "If I play well tomorrow, good chance."
Kim could take over as world number one in the rankings with a win this week along with Ko finishing solo 10th or worse.
England's Georgia Hall (68) had a relatively quiet start to the day with eight pars and a lone bogey on the front nine but stormed home with five birdies over her last eight holes to sit alone in third place and three shots back of Kim.
"I hit it pretty good today as well. I just didn't hole many on the front nine, so I had to stay patient," said Hall, who won her lone major at the 2018 Women's British Open.
"Managed to get a couple early in the back nine and then just followed in from there really."
Five players are tied for fourth at nine under, including past champions Charley Hull (2016) and Lexi Thompson (2018) and world number six Brooke Henderson, one of six players to card the day's low round of six-under-66.
(Reporting by Frank Pingue in Toronto; editing by Grant McCool)
