American Christina Kim has grabbed a one-shot lead after the first round of the $US1.7 million ($A1.75 million) LPGA State Farm Classic.
Runner-up in the event last year, Kim notched four birdies in a row from the 11th, and eagled the par-five 16th en route to a nine-under 63 at Panther Creek Country Club.
"It's really exciting to be at the top of a leaderboard again," said Kim, who is seeking her third LPGA Tour title.
The 24-year-old Californian posted a total of seven birdies in her bogey-free effort.
She led South Korean Sun Young Yoo, who started on the back nine and tied the tour record by playing that side of the course in eight-under.
American Kristy McPherson, who played a bogey-free round, and South Korea's Jee Young Lee were tied for third at seven-under.
Playing in her sixth LPGA tournament of the season, Michelle Wie started on the back nine and overcame a bogey on the 10th with a brace of birdies and an eagle in her next four.
Despite finishing four strokes behind the leader at five-under, the 18-year-old Hawaiian said she could have done better.
"I missed birdie chances at the last three holes," Wie said.
"It's great to shoot a low score, but today's over and done with, and now I want to focus on tomorrow.
"There are a lot of birdie holes that I missed out on today and, hopefully, I can get them tomorrow."
Australia's Wendy Doolan is alongside Wie on 67.
Defending champion Sherri Steinhauer, who went wire-to-wire last year to edge Kim by one stroke, struggled early.
She had three bogeys in her three-over 75.
Steinhauer, who could become the 16th player in tour history to surpass $US6 million ($A6.17 million) in career earnings, is looking to become the fourth player to win this title in consecutive years and first since Beth Daniel in 1989-90.
With the Evian Masters, the Women's British Open and the Canadian Women's Open looming on the schedule, a number of top players elected to skip this event.
World No.1 Lorena Ochoa of Mexico, Sweden's Annika Sorenstam and American Paula Creamer are among the notable absentees.
"It does not matter if Lorena Ochoa is here or not. If someone wants to win and they really, really want it, it's going to happen," Kim said.