South Korea's Kim In-Kyung fired a bogey-free seven under 65 to take a one-stroke lead after the first round of the LPGA Tour's Portland Classic.
Kim, who teed off in the final group of the day, on Thursday used a string of four straight birdies on the back nine to record her lowest round of the season by two strokes.
"I hit the ball well and made some putts coming down. This is a really good golf course," Kim said. "You have to hit the good shots and also make putts. There's a couple of tricky pins, but I was able to manage."
Americans Jennifer Song and Amelia Lewis are tied for second place at six-under at the Columbia Edgewater Country Club.
Anna Nordqvist, who has two victories this season, shot a five-under 67. She was joined in fourth place by Laura Diaz, Paraguay's Julieta Granada, Mina Harigae, Alison Walshe, Emma Jandel and Paula Reto of South Africa.
US Solheim Cup captain Juli Inkster carded a four-under 68. Inkster is tied for 11th in a group that includes France's Karine Icher, Chella Choi, Jennifer Kirby, China's Lin Xi Yu and Jacqui Concolino, of the US.
Kim, who is seeking her fourth career win on the US LPGA Tour, recorded her last victory in North America four years ago at the Lorena Ochoa Invitational.
In 11 starts this year, she has one top-25 finish at the Swinging Skirts LPGA Classic.
"Seems like every week it's like 66, 65," said Kim, who won on the Ladies European Tour earlier this year. "So I didn't really think about scoring that much. With this golf course you just gotta play your game, and then you get rewarded."
Defending champion Suzann Pettersen shot one-under 71 and is six strokes back of Kim in a tie for 39th. Amateur qualifier Gigi Stoll had three birdies and two bogeys to match Pettersen with a 71.
Natalie Sheary was disqualified for signing an incorrect scorecard and Irene Coe withdrew during the first round with a back injury.
Source: AFP