Australia's Hannah Green added the LPGA Portland Classic crown to her Women's PGA Championship title Sunday, outdueling US teenager Yealimi Noh down the stretch on the way to a one-shot victory.

The 22-year-old from Perth went into the final round three shots behind 18-year-old Noh, who had played her way into the field in Monday qualifying.

Green had six birdies in her five-under-par 67 at Columbia Edgewater Country Club and finished with a 21-under total of 267 while Noh posted a one-under 71 for 268.

Green, who made her first LPGA title a major when she won the Women's PGA in June, curled in a long birdie putt at 17 to pull even with Noh.

A six-footer for par at 18 was enough as Noh closed with her third bogey of the day.

"This golf course is quite tough," said Green, who had followed a career-best 63 on Friday with a disappointing 73 on Saturday to fall out of the lead.

"I had to stay patient," she said. "I just needed to make sure I was giving myself opportunities, I think I did that really well."

Green became the fifth multiple winner on the LPGA tour this year. She's the first Aussie to win multiple titles in one season since Minjee Lee in 2016.

Noh, who turned professional in January when she was still 17, had four birdies on the day and still led by three with four to play. But she made two of her three bogeys in the last three holes as Green kept the pressure on.

"She stayed really strong throughout, so congrats to her," said Noh, who had been hoping for a victory that would give her LPGA membership without having to go through qualifying school.

"It's hard," Noh admitted. "I tried my best today."

American Brittany Altomare posted a final-round 69 to finish third on 271.

Japan's Nasa Hataoka posted the low round of the day, a 66, to share fourth place on 273 with Canadian Brooke Henderson, who carded a 71. Henderson is the last player to win an LPGA title after coming through Monday qualifying. She did it in Portland in 2015.