French rookie Adela Cernousek is the surprise first-round leader of the LPGA Tour's Portland Classic after firing an eight-under 64 to lead some of the game's best players.

The 22-year-old turned in an exceptional second nine on Thursday at Columbia Edgewater Country Club, leaving her one stroke ahead of Gurleen Kaur, Miranda Wang, two-time Portland champion Brooke M. Henderson and South Korean duo Jeongeun Lee5 and Sung Hyun Park.

After starting on the back nine and making one birdie and eight pars, Cernousek stormed home.

She charged up the leaderboard by making birdies on the first, fourth, fifth and sixth before eagling the seventh. Cernousek then added a birdie on the last for good measure.

"No, I was just trying to do the same thing," Cernousek said when asked if she played more aggressively closer to the greens on the back nine.

"Like hit the fairways, get close to the pin and try to make the putts, like have good speed on the putts.

"I think I was hitting the ball very well. My caddie really helped me with distances. I think I always had like very close putts for birdie. I was able to make a lot of them, so it was great. I felt very good with my whole game, yeah."

The 2024 individual NCAA champion for Texas A&M, Cernousek is making only her 13th LPGA start. She has made just three cuts as a pro, never ending up in the top 20.

South Africa's Ashleigh Buhai, Sweden's Linn Grant, South Korea's Haeran Ryu, Thailand's Arpichaya Yubol and France's Perrine Delacour are two strokes back at 66.

Eight players, including past Portland winner Jin Young Ko of South Korea, amateur Kiara Romero and Australian Gabriela Ruffels, are tied for 12th at 67.

Ruffels made birdies on the second and fourth, sandwiched by a bogey on three, before another bogey on six was rubbed out by a birdie on the seventh for a one-under 35.

But she steadied in the second nine, making four birdies including the last, without any bogeys to be tied 12th. 

At five under, Ruffels is just three behind leader Cernousek and one better than compatriot and newly crowned major champion Grace Kim.

The 2025 winner of the Evian Championship, Kim's four-under total included seven birdies and three bogeys.

Kim made 33 on the back nine that included a bogey on the very last hole.  

Henderson, the Portland champion in 2015 and 2016 at ages 17 and 18, opened and closed her round effectively. Starting on the back nine, she birdied her first four holes, and she concluded her bogey-free rounds with birdies on three of the final five holes.

"It was a really awesome start, four birdies in a row," Henderson said. "I mean, that's an ideal start any week, especially here. I love coming back to this place. I do have a lot of the great memories. A lot of good things happened to me here.

"So just tried to keep it rolling after that great start and was able to capitalise with three birdies on the back nine to get a little bit closer to the top of the leaderboard."

Defending champion Moriya Jutanugarn of Thailand is tied for 97th at 73, along with Hannah Green, the 2019 US Women's PGA champion from Perth.

with AAP