Yealimi Noh hits on the 16th hole during the third round of the LPGA Cambia Portland Classic on Saturday in Portland, Oregon. Photo: VCG

US teenager Yealimi Noh fired eight birdies in an eight-under-par 64 on Saturday to take a three-shot lead over Hannah Green after three rounds of the LPGA Portland Classic.

Noh, who made the field through Monday qualifying, posted the low round of the day at Columbia Edgewater Country Club in Oregon for a 19-under-­par total of 197.

"I was hoping for a good week, but to be in contention, I'm really excited," said Noh, who turned professional in January at age 17.

"Yesterday, too, I was just like, I couldn't really sleep. I was excited to come out and try to move on moving day."

She roared past Australia's Green, who held a five-shot overnight lead after rounds of 64 and 63 but finished the day with a one-over 73 that left her on 200.

"The greens were a lot ­quicker, I think a lot quicker than the practice green and maybe that threw a few people off," said Green, winner of the Women's PGA Championship this year for her first LPGA title.

"It certainly surprised me once I got out there, and I still found it really difficult, even towards the end of the round, to get the pace correct," added Green, who had back-to-back birdies at the fourth and fifth but three bogeys the rest of the way - including at 18.

"But the pins, I didn't find too difficult," Green added. "You could easily be on the wrong side of the pin, but I think just with it becoming a bit firmer and a little bit of wind made a huge difference today."

South Korea's Kim Sei-young also seemed to feel it, following up her 11-under 61 of Friday with a 73 that left her eight off the pace.

Canadian Brooke Henderson and American Brittany Altomare shared third on 202. Henderson carded a 67 while Altomare signed for a 68.

Henderson is the last Monday qualifier to win an LPGA tournament, a victory that came at the 2015 Portland Classic.

She recalled being "just terrified" as she set out in the ­final round with a five-shot lead that she was determined not to squander.

But Henderson added, "It's the opportunity of a lifetime, and you can make it easier on yourself if you can go out and play one round well, as opposed to going to Q-School. If you can capitalize, it changes your whole life."

That's not lost on Noh, who with a win would gain membership to the LPGA tour which she could take up immediately or defer to the 2020 season.

"It would change my entire like, year, my life," she said when asked what a win would mean to her.

"That would just be a dream come true."