Jessica Korda shot a five-under 67 on Friday afternoon in warmer-but-still-chilly conditions at Lake Merced to take a one-stroke advantage into the weekend of the LPGA's Mediheal Championship.
The winner in Thailand in February in her return from reconstructive jaw surgery, the long-hitting Korda had six birdies - three on the first four holes - and a bogey to reach nine under.
"It's only Friday, still two more days to go," Korda said.
"Play the same way I have been the last two days.
"Hopefully, some putts drop. Stay patient and stick with my process."
Monday qualifier Annie Park was second after a 66 in the morning.
"I battled some injuries last year and coming back was tough," Park said.
"I like I am where I am right now, so it feels good."
England's Charley Hull was alone in third at seven under after a 68 while former world No.1 Lydia Ko had a 70 to get to six under.
The New Zealand 21-year-old won the Swinging Skirts LPGA at Lake Merced in 2014 and 2015.
"I think just put myself in good positions," Ko said.
"This is a course where you need to drive it well and putt well.
"Hopefully, I'll continue doing that and just stay patient and stay confident."
Moriya Jutanugarn, the winner Sunday in Los Angeles for her first LPGA Tour title, shot 68 to join Sei Young Kim (70) at five under.
Australian Minjee Lee, the 2012 US Girls' Junior champion at Lake Merced, shot a 70 to match her countrywoman Su Oh (72), So Yeon Ryu (70) and Nasa Hataoka (69) at four under.
"It's a second-shot golf course. Obviously, you need good drives as well, but I think your shots into the greens are really important," Lee said.
"I think I've been judging the wind OK, but I could probably improve on that, and pretty much just taking advantage of the short putts that I have when I can."
Hannah Green signed for a 71 to be at even par and rounbd out the Australian contingent playing on the weekend.
