SAN FRANCISCO -- Lexi Thompson needed to get her mind right before she could her golf game back and now is in position to win her second career major.
Thompson shot a bogey-free 5-under 66 on Saturday to take the lead into the final round of the U.S. Women's Open for the first time in her career with a one-shot edge over teenager Yuka Saso.
"I haven't played to my standards and what I need, and I just realized that I needed to change my mindset," Thomson said. "It was only hurting me. Obviously, I needed to work on some technical things in my game and everything, but the mental side was really getting to me. I was just taking it way too seriously and thinking that Lexi depended on my score."
Thompson added, "I love playing in front of people and just seeing those little kids and hearing the chants, it just, it brings me happiness and a reason to play golf again."
As Thompson chases her first U.S. Women's Open title and second major, she said that she has been working hard on her mental game with performance coach John Denney. In both 2016 and 2017, Thompson worked with Denney on her mental game and said that she's currently using a practice of spirituality and gratitude when on the course.
"Just being grateful for everything in my life and being grateful that I have the opportunity to be able to play a golf course like this or any golf course. ... Whether I play good or bad it's still an amazing experience."
Thompson said she has been taking strides toward not dwelling on mistakes, although she made few Saturday when she was the first player all week to make par or better on every hole in the round.
That had her in the lead at 7 under heading into the final round of a major for the first time since 2017, when her edge after 54 holes at the ANA Inspiration was erased on Sunday when she was penalized four strokes after a viewer saw that she had misplaced her marked ball during the third round.
Thompson still managed to make it into a playoff against So Yeon Ryu, but she lost and was unable to add to the 2014 ANA Inspiration title she won for her first major.
Thompson played a nearly flawless round Saturday in her 15th try at her first U.S. Women's Open title after first competing as a 12-year-old amateur in 2007. She has four top 10 finishes at the U.S. Women's Open, including a runner-up two years ago in Charleston.
Thompson has been lurking around the leaderboard all week, shooting 69 on Thursday and 71 in the second round before shooting the low round of her career at this tournament on Saturday.
She started to make a run with three birdies, including one on No. 9 after hitting her tee shot into the second cut of rough. She still managed to get on the green and made a 20-foot putt to get to 5 under.
Thompson added another long birdie putt on No. 14 and reached the green at the par-5 17th in two shots before two-putting for birdie and the lead. She saved par with a 3-foot putt at 18 after hitting her tee shot into the rough and her approach behind the green.
"I struck it well all day, made a few good putts out there," she said. "It's all about patience out on this golf course because there's going to be bad shots made and you're going to miss some fairways, so you just have to get bogey at worst and get off the hole and go on to the next."
Saso made back-to-back bogeys on the back nine to fall out of the lead before recovering with a birdie at the par-5 17th to get back to 7 under. She missed a 12-foot par putt on 18 and ended the day a stroke back.
New Jersey high school amateur Megha Ganne shot a 72 and was tied for third at 3 under with 2019 champion Jeongeun Lee6 of South Korea.
China's Shanshan Feng was fifth at 2 under, with Japan's Nasa Hataoka and American Megan Khang the only other players under par at 1 under.
Saso, who has never finished better than sixth in an LPGA Tour event, will play in the final group on Sunday with a chance to join South Korea's Inbee Park as the only teens to win this tournament. Park did it at 19 years, 11 months, 17 days in 2008, which will be Saso's exact age Sunday.
The 17-year-old Ganne was a crowd favorite at the course and kept her composure early with a couple of early par saves and birdies on the fifth and ninth holes to get within a shot of the lead at 5 under. Back-to-back bogeys to start the back nine knocked her down the leaderboard before she steadied herself with seven straight pars to end the day.
"It was really mentally a grind out there and I've never had to just perform from such bad lies and situations hole after hole and still believe that I was going to do it again on the next hole," she said. "So it was a lot, but I'm confident in how I'm playing."
Lee6 got to 6 under with a birdie at No. 4 but fell off when she hit her tee shot into the deep rough at No. 5 and ended up with a double bogey.
ESPN's Charlotte Gibson contributed to this report.