By Rory Carroll
SAN FRANCISCO (Reuters) -A relaxed Lexi Thompson fired a flawless 66 at the Olympic Club on Saturday to vault to a one-stroke lead heading into the final round of the U.S. Women's Open in San Francisco.
All facets of Thompson's game were working as she carded her lowest round at the major in 15 appearances, sinking five birdies and gamely scrambling to avoid any bogeys to sit seven-under 206 for the tournament, one clear of Yuka Saso.
The popular American smiled and signed autographs as she walked the sloping Olympic Club's Lake Course on a sunny day and said the work she has put in to improve her mental fitness was making a difference in her game.
"I haven't played to my standards and I realized that I needed to change my mindset," she told reporters.
"It was only hurting me. Obviously I needed to work on some technical things in my game and everything, but the mental side, I think, was really getting to me," she said.
"I was just taking it way too seriously."
Overnight leader Saso, 19, looked poised to run away with the tournament when she jumped out to a three-stroke lead but back-to-back bogeys on 13 and 14 opened the door for Thompson.
The Filipino player with an sharp short game pulled even with Thompson after completing a tough up-and-down on 17 but a bogey on the last left her in solo second place.
In the hunt at three-under were high school student Megha Ganne and 2019 champion Lee6 Jeong-eun, with the dangerous Shanshan Feng of China one shot further adrift.
Saso said she enjoyed the vocal support she received from the limited number of fans in attendance and said she was looking forward to her final round grouping with Thompson and friend Ganne.
"I'll be rooting for her too," Saso said with a laugh when she was told that Ganne had said that if she was not in the tournament, Ganne would be pulling for her fellow teenager.
"We have known each other for years, we played together in junior tournaments and she's really nice."
Ganne, the amateur turned talk of the tournament after she finished the first round as an unexpected co-leader, received rock star treatment from the fans in San Francisco and said she relished the spotlight.
"It was so fun," she said.
"I've always imagined myself engaging with the fans like that because when I was younger and watching events, I loved it when I would see the pros just even look at the crowd or smile or do anything like that.
"So I really wanted to embody that today and I got a chance to on a few holes, which was nice."
The 76th edition of the major marks the first time that it has been played at the iconic Olympic Club, a course that has hosted five men's U.S. Opens.
The men's U.S. Open will also be held in California this month at Southern California's Torrey Pines.
(Editing by Pritha Sarkar and Christian Radnedge; Editing by Michael Perry)