Hannah Green and Gabriela Ruffels are four shots off the pace after the opening round of the women's Canadian Open in Vancouver.
The Australians both fired two-under 70s, along with American world No.2 Nelly Korda and Perrine Delacour of France, to trail Japanese leader Yuka Saso (66).
Linn Grant is second after an afternoon 67, while former world No.1 and 2019 tournament champion Jin Young Ko is in a group of six players at three under.
Saso had a big second nine on Thursday. Even par at the turn at tree-lined — and mosquito-infested — Shaughnessy Golf and Country Club, the 22-year-old who won the 2021 US Women's Open for her lone LPGA Tour title birdied Nos. 1-4 plus six and seven.
"I don't know what happened the back nine," she said.
"I started hitting some good second shots and having short putts for birdies, giving myself a lot of chances."
Defending champion Paula Reto of South Africa shot 78, as did Sydneysider Steph Kyriacou.
Fellow Aussies Su Oh and Karis Davidson had two-over 74s, while Grace Kim and two-time major winner Minjee Lee shot 75s.
Grant, the 24-year-old Swede who won July's Dana Open in Ohio for her first LPGA Tour title, rebounded from a bogey on the par-5 11th with birdies on the next four holes.
"I didn't feel very confident with my swing going out," she said.
"But I managed to kind of find something. You know, golf is golf. You got to just kind of go with what you have."
Rose Zhang, the 20-year-old won at Liberty National in her first professional start in June, shot a 69, while three-time winner Lydia Ko had a 72. She won at Vancouver Golf Club in 2012 and 2015.
Race to CME Globe leader Lilia Vu also shot a 72 and Lexi Thompson opened with a 76. She's No.157 in the race and in danger of losing her LPGA card without having to use a one-time career money exemption.
2018 winner and Canadian star Brooke Henderson (75) struggled while playing in glasses for the first time on tour.
"I just wasn't sharp today," she said.
"At least I could see my ball in the bush, which was kind of a good thing, I guess."
Shaughnessy was originally set to host the event in 2020, but the COVID-19 pandemic delayed it by three years.