April 1 American Lexi Thompson built on her success at the ANA Inspiration with a third-round five-under-par 67 on Saturday to grab a two-shot lead heading into the final round.
Thompson completed the final 10 holes of her delayed second round early in the day, carding a 67, and then returned to make six birdies and one bogey in her third round to reach 13-under.
Norwegian Suzann Pettersen shot a third-round 68 and was two back at 11-under.
At 10-under 206 were South Koreans Hur Mi-jung, Park In-bee and Ryu So-yeon and Minjee Lee of Australia.
Tied at eight-under 208 were Cristie Kerr, Michelle Wie, Ariya Jutanugarn of Thailand and Karine Icher of France.
The 22-year-old Thompson has twice held the 54-hole lead in this event, going on to win in 2014, and is looking for her second Major victory.
"Yeah, well, that experience always helps me out, but I'm just going to focus on tomorrow, focus on one shot at a time, relax out there between shots and just focus on doing my routine," Thompson told reporters.
Pettersen is a 15-time winner on the LPGA Tour but has never won a major. She has finished as the runner-up three times at the event at the Mission Hills Country Club course.
"I'm driving the ball well and that's a major key on this golf course," Pettersen said. "And if you do, you can kind of attack it as well. So far, so good. I've got a big job to do tomorrow.
"I mean, the leaderboard is packed behind me as well. You've got to expect to go out there and shoot low. There's a lot at stake, but I'm all in for it." (Writing by Jahmal Corner in Los Angeles; editing by Sudipto Ganguly)