China's Muni He made a 35-foot birdie putt on the 22nd hole to beat qualifying medalist Mariel Galdiano on Wednesday in the first round of the U.S. Women's Amateur.

"My goal was really just to roll it near the hole because it's not an easy putt," He said. "It's a pretty slopey putt and a very decent break, but I just kind of had a target in mind and putted it toward there and let it roll near the hole. It just happened to go in."

The 17-year-old He got the last of the 64 spots in match play Wednesday morning in a playoff, holing a 22-foot birdie putt on the second extra hole. She three-putted for bogey on the first playoff hole Tuesday, and had to return Wednesday to fight four other players for the last position.

"Today, as I stood out there in the playoff, to get in really, I felt a lot better about my game, whether it was my putting, my stroke or my shots in general," said He, set to attend the University of Southern California in 2017. "I think that's what kept the momentum going."

The 18-year-old Galdiano, from Pearl City, Hawaii, dropped out a day after setting the championship stroke-play qualifying record at 9-under 133. She became the third straight medalist to fall in the first round, following Bethany Wu in 2014 and Angel Yin last year.

"She played really well, obviously, and these things happen for a reason," said Galdiano, preparing for her freshman season at UCLA. "It's just another learning experience for me."

Galdiano forced extra holes with a 12-foot birdie putt on the par-5 18th. She made the only two bogeys of the match, the first on the par-4 14th to drop into a tie and the second on the par-5 17th to fall a hole down.

He will face NCAA champion Virginia Elena Carta of Duke on Thursday. Elena Carta, from Italy, topped Rinko Mitsunaga of Roswell, Georgia, 5 and 4.

Dylan Kim of Plano, Texas, had the shortest match, routing Lauren Beaudreau of Lemont, Illinois, 8 and 7. Playing her first competition since surgery to remove a benign tumor from her left hip in October 2015, Kim will be a sophomore at Baylor.

"I put it really close the first few holes, so I was hitting my irons really, really well," Kim said. "I'm putting well from that mid-range area, from 10 to 15 feet, so it was really nice to get some birdies in early."

Kristen Gillman of Austin, Texas, the 2014 champion, cruised to a 5-and-4 victory over Annika Clark of Highlands, Texas. Second-seeded Lucy Li pulled away to beat August Kim of St. Augustine, Florida, 4 and 3.

Eun Jeong Seong, the 16-year-old South Korean player coming off her second straight U.S. Girls' Junior title last month, topped Janet Mao of Johns Creek, Georgia 4 and 3.

Hannah O'Sullivan, the Arizona teen who won last year in Portland, Oregon, skipped her title defense. She played last week in the Women's British Open.