Yuka Saso of the Philippines relinquished her hold of the lead at the US Women's Open on Saturday, but remained very much on course to achieve history for her country.
Saso staved off American Lexi Thompson's charge at imposing The Olympic Club Laker Course early on, but the reigning Asian Games champion stumbled midway through the back 9, bogeying the par-3 No. 13 and the par-4 No. 14.
Thompson, bogeyless on the day, overtook Saso by one shot at that point, before the Filipina recovered with a birdie on the par-5 17th looking to match Thompson's output on the day.
But Saso bogeyed the par-4 18th to fall to second place heading into the last round.
Thompson, who hit a 66 on the day including 5 birdies, was at 7-under 206, one shot ahead of Saso (71, 207).
US amateur Megha Ganne, a 17-year-old New Jersey high school student, kept herself in contention with a one-over par 72 that left her sharing third on 210 with South Korean Lee6 Jeong-eun, who battled her way to a two-over 73.
China's Feng Shanshan was alone in fifth after a 72 for 211.
Thompson was the first player to post a bogey-free round this week at Olympic Club, which has hosted five men's US Opens but had never before hosted a women's major.
The 2014 ANA Inspiration winner is seeking a first US Open title in her 15th attempt. She first competed in the championship as a 12-year-old amateur in 2007.
"Honestly, I just thought my patience of being out there," Thompson said of the key to her lowest career round in a US Open.
"I struck it well all day, made a few good putts out there. And I guess probably just picking up the missed fairways or missed greens when I did, getting up-and-down or just getting it as far as I could out of that rough.
"It's all about patience out on this golf course."
Thompson climbed the leaderboard with 3 birdies on the front nine. She curled in a long birdie putt at the 14th and had the solo lead at seven-under after a birdie at 17 -- where she tapped in after narrowly missing her eagle attempt. -- With a report from Agence France-Presse
Leading scores after Round 3 (United States country of origin unless noted, a-denotes amateur, par-71):
206 - Lexi Thompson 69-71-66
207 - YUKA SASO (PHI) 69-67-71
210 - a-Megha Ganne 67-71-72, Lee6 Jeong-eun (KOR) 70-67-73
211 - Feng Shanshan (CHN) 69-70-72
212 - Nasa Hataoka (JPN) 72-69-71, Megan Khang 68-70-74
213 - Park In-bee (KOR) 71-69-73
214 - Angel Yin 68-79-67, Kim Hyo-joo (KOR) 72-70-72, a-Maja Stark (SWE) 71-70-73