JERSEY CITY, N.J. -- So Mi Lee shot a 6-under 66 after getting into the field less than two hours before her tee time and took a two-shot lead Thursday after the opening round of the Mizuho Americas Open got off to a surprising start with the withdrawal of defending champion Rose Zhang because of illness after three holes.
Withdrawals were one of the stories of the first round. Besides Zhang, who was coming off a win in the Cognizant Founders Cup last weekend, Maja Stark of Sweden and Caroline Masson of Germany also withdrew because of illness.
Lee, 25, of South Korea replaced Stark, and Mao Saigo, 22, of Japan got Masson's spot. They are right at the top of the leaderboard.
A five-time winner on the Korean LPGA tour, Lee had eight birdies and two bogeys in her round on the Liberty National course in the shadow of New York City. Saigo had five birdies and a bogey in finishing tied for second with three other players with 68s.
Also at 4 under were rookie Gabriela Ruffels of Australia, American Andrea Lee and Bianca Pagdanganan of the Philippines.
Celine Boutier of France, ranked No. 3 in the world, No. 8 ranked Minjee Lee of Australia and Jennifer Kupcho, who lost this event to Zhang in a playoff last year, were in a large group at 3 under. It was another shot back to another large group at 2 under led by Nelly Korda, who had her record-tying five tournament winning streak snapped last week.
Despite shooting 1 over in each of her final two rounds last week, Korda still finished tied for seventh in an event that was a two-player race in the final round between Zhang and Madelene Sagstrom of Sweden.
Zhang won't be around to beat Korda this week after playing her first three holes in 2 over and leaving because of an intestinal issue.
"I was really looking forward to trying to defend my title, but unfortunately spent the last 12 hours with really bad intestinal pain," Zhang said in a statement on social media.
With Zhang out of the tournament, it was appropriate for another Stanford player to step up.
Andrea Lee, who saw Zhang break most of her records for the Cardinal, had a run of four straight birdies at Nos. 4-7. She twice got to 5 under on the back nine, but had bogeys each time.
Ruffels is the top rookie on the tour this year with two third-place finishes, including a solo third last week. The 24-year-old had four birdies in a bogey-free round.
"I feel like definitely getting more comfortable," said the Australian golfer who was the Epson Tour player of the year in 2023. "I mean, I feel like the confidence definitely goes up when you have a few good results and I've been fortunate to have a few good results this year."
So Mi Lee never thought she would get into the tournament, and she sent her caddie home.
"I didn't expect to play today, so I just go to the park and going to run, but my father said, 'Hey, just go and [have] some practice and you have a chance,'" Lee said through an interpreter.
When she got into the tournament, her father, Tohyeun, became her caddie.