West Australian major winner Hannah Green had to wait an extra day to open her title defence at the LPGA's Portland Classic.
Once she got going, about the only thing that slowed her was a lightning delay and fading light.
Green shot a 6-under 66 at Columbia Edgewater for a share of the lead with American Cydney Clanton in the event reduced to 54 holes because of poor air quality caused by wildfires.
Green was able to finish in fading light, while many other afternoon starters were still on the course when darkness suspended play.
"I'm super happy that we finished and super happy with my round," Green said.
"I did bogey my last hole, but obviously did some great things out there.
"Putted really well, so I need to continue that.
"I'm kind of glad that I have a quick turnover. Hopefully, I can continue the momentum tomorrow."
The 23-year-old Perth native won the Women's PGA Championship just months before her win in Portland in a breakthrough 2019 season.
On Friday, Green birdied four of the first five holes and returned from the weather break to add another on the par-5 7th.
After missing birdie chances on the two back-nine par 5s, she birdied the par-3 13th and 16th and closed with a bogey on the par-4 18th just before sunset.
Last year, she matched the tournament 72-hole scoring record at 21 under.
"It's obviously really soft," Green said.
"We've had a lot of rain today, so it's very different conditions to last year.
"So you can be quite attacking I guess with the pins... "
Caroline Masson, Amy Olson, Gaby Lopez and Mel Reid shot 67, while Yealimi Noh also was 5 under with a hole left to finish to be tied third at the end of the day's play.
World No.5 Minjee Lee of Australia carded a two-under 70 to be in a group sharing 23rd with Mirim Lee, the ANA Inspiration winner from last week.
Australian amateur Gabi Ruffels is at one-under along with last month's Women's British Open champion Sophia Popov of Germany.
Season points leader Danielle Kang, the World No.3, matched 2017 winner Stacy Lewis with a 72.
Sarah Kemp (73), Su Oh (74) and Sarah Jane Smith (76) round out the Australian contingent.