Chasing her second LPGA victory of the season, Jin Young Ko shot a five-under 67 on Friday to take the lead midway through the Cambia Portland Classic.

The world No.2 needed only 23 putts in her morning round, making six birdies and a bogey to reach eight-under 136 at the hilly, windy and tricky Oregon Golf Club.

"I changed the putter few weeks ago in Korea and I spent time, over a month, in Korea, so I feel really like comfortable and like fresh," Ko said. "I'm playing really good right now."

Gemma Dryburgh of Scotland was a stroke back after a 69.

"It was quite tough out there. It was quite windy," Dryburgh said. "Reminded me of home a little bit, especially my back nine, the front nine. It's a bit more open around there so it's kind of tricky."

Carlota Ciganda, the only member of the winning European Solheim Cup team in the field, had a 71 to get to five under.

"It was a tough day," Ciganda said. "Took three hours to play the front nine, so it's just a tough course. It's a new course. It was really windy today. The front nine is playing quite tricky with the side winds."

One behind Ciganda in joint fourth position is Australia's Su Oh (71), Jeongeun Lee (67), Jeongeun Lee6 (70), Andrea Lee (68), Alana Uriell (66), Jenny Shin (71) and Pajaree Anannarukarn (72).

Oh had an up-and-down round, mixing one double bogey with three bogeys, four birdies and an eagle.

Compatriot Katherine Kirk (72) at three over is tied 41st while Hannah Green (77) just made the cut at six over.

Making her first start since the Tokyo Olympics, Ko rebounded after bogeying three straight holes late Thursday afternoon in an opening 69. She won in Texas in July for her eighth LPGA Tour victory.

"These fairways and greens are really narrow, so I had to hit it straight or like perfect shot," Ko said. "So, it was a little nervous from the tee for everybody, but did I great job. I'm looking forward to the weekend."

Laura Davies, at 57 the oldest player in the field, followed her opening 70 with a 75 to fall to one over. Brooke Henderson, the 2015 and 2016 winner, was two over after a 76.

Oregon State senior Ellie Slama advanced to the weekend at three over, following an opening 78 with a 69.

Stacy Lewis, the 2017 champion, missed the cut by a stroke with rounds of 73 and 78.