SAN MARTIN, Calif. — When Mirim Lee walked off the course after her record-tying round, she described her day with words usually not heard when talking about the U.S. Women's Open.
"So today's round was easy day — easy round, yeah," Lee said.
She sure made it look that way Thursday when she became the fifth golfer to shoot a round of 8 under at the U.S. Women's Open, making 10 birdies on the way to a 64 to take the first-round lead at CordeValle.
With the greens not quite as firm as they likely will be later in the week and the wind not playing a major factor, there were low scores to be had throughout the field — at least for the opening morning of the tournament, when 23 players shot under par, including six of the top seven on the leaderboard.
"I definitely expect it to change," said Christie Kerr, who was three shots behind Lee in a tie for second. "I don't think the USGA likes when we shoot 8 under on their golf course. You have to expect it to change, and if it doesn't, then you'll have opportunities to score."
The play got much tougher in the afternoon, when the wind picked up and only 14 players were under par, led by Amy Yang, who birdied 18 to move into a three-way tie for second at 5 under with Kerr and Minjee Lee.
None of the players in the marquee group of three of the top four players in the world — Lydia Ko, Brooke Henderson and Lexi Thompson — could break par. Ko birdied her final hole at No. 9 to finish the day 1 over, one shot ahead of Thompson and three in front of Henderson.
Those three need to do plenty of work to catch Lee.
"I don't know what course (Lee) played," Ko said. "Maybe the ladies tees; maybe a different course. But she played fantastic. We were checking the leaderboard. She made two bogeys and still shot 8 under. It's very impressive. She must have hit a lot of fairways and made good putts. I think obviously that's the key."
Lee is the first woman to shoot that much below par at the U.S. Open since Lorie Kane and Becky Iverson did it in the second round in 1999 at Old Waverly in Mississippi. The lowest total score in a round in U.S. Open history is 63 by Helen Alfredsson in 1994 at the par-71 Indianwood in Michigan.
Lee capped her record day with birdie from about 8 feet on her final hole, the par-5 ninth, to take a three-shot lead over fellow South Korean Minjee Lee and Kerr after the morning groupings.
"The course is perfect now," Mirim Lee said. "Greens are really fast."
Kelly Tan, Brittany Lang and Anna Nordqvist were four shots back at 4 under. Nordqvist hit all 18 greens in regulation, the first time that has happened at the U.S. Open since the statistic started being tracked in 1986.
Defending champion In Gee Chun, followed by about a dozen members of the Flying Dumbo fan club wearing shirts that Chun designed, hit back-to-back bogeys on the front nine and finished 1 over. Chun is seeking to become the eighth player to repeat as U.S. Open champion and first since Karrie Webb did it 15 years ago.
Seminole's Brittany Lincicome shot 75 and was 3 over.