Lydia Ko has fired another strong round at the LPGA Tour's season finale CME Group Tour Championship but still trails red-hot leader Celine Boutier.
Ko followed up a three-under 69 on Friday with a four-under 68, which included five birdies and a lone bogey.
Her improved second round leaves Ko sitting in a tie for 13th place at seven-under, just three shots behind a trio of women in second place, but seven behind Boutier.
The 28-year-old from France made seven birdies over her last 10 holes for a second-consecutive round of 65 and a four-shot lead.
"Yesterday I thought was a little bit rusty. Didn't hit the ball that great and didn't putt that great either. Today I hit the ball extremely well," Ko said following her round, implying there was more in the tank for a run at the leaders.
"I feel like even last week I left a lot of putts out there. That was kind of the case again today."
For so much of the wind-blown second round, a dozen or so players were separated by one shot at Tiburon Golf Club. That included Nelly Korda and Jin Young Ko, four-time winners this year in a battle for LPGA player of the year.
Over the final two hours, Boutier left them all in her wake in the chase for the $US1.5 million prize.
Among her seven birdies, the 28-year-old from France chipped in from short of the green on the 13th, stuffed her approach to 4 feet behind the hole on the 15th, reached the middle of the green on the par-5 17th in two for an easy birdie and closed with a 7-foot birdie putt.
She was at 14-under 130, four ahead of Gaby Lopez of Mexico (68), Evian Championship winner Minjee Lee of Australia (68) and Mina Harigae (69).
"I was frustrated with my front. I left a couple of shots out there," Boutier said. "My long game was really solid all day, and I was able to put my shots close, and it was helpful on the back."
Korda, who has a 10-point lead over Young Ko in the race for player of the year, was in the group five shots behind after having to settle for a 69.
The 23-year-old US star was right there in the mix until she was slowed by one swing. She went for the green on the par-5 14th and it peeled to the right on her, just inside the hazard line. Korda still had a swing, but her punch shot didn't make it up the slope, and she failed to get up-and-down from there to take bogey.
"I just hit it a little heely and it just floated out to the right," Korda said. "That's usually my miss. The ball is above your feet. I was trying to be a little aggressive with it, and my misses have been a little left, so I kind of lifted up and hit it out to the right."
Young Ko had a 67 and was in the group six shots behind. More relevant to player of the year, Ko was two shots away from a chance to finish second, which she has to do for any chance to capture player of the year for the second time, and even that depends on how Korda fares.
- with AP