Sydnee Michaels and Mika Miyazato both produced seven-under 65s in sweltering heat to take the lead at the Safeway Classic.
Michaels: First LPGA season
The temperature at Pumpkin Ridge's Ghost Creek Course in California reached 100 degrees on Friday, making the first round a real struggle for the pros.
Miyazato and Michaels dealt with the conditions best on the day, each carding eight birdies to share the first-round lead.
Rookie Michaels is coming off a career-best tie for 21st place at last week's Toledo Classic.
"It's been hit or miss," Michaels said. "I'll be in contention and I might have a little shaky Sunday, and wind up top 30 or something like that or I'll miss the cut by one or two.
"I definitely feel that every week I learn something, and I'm hoping I'll start to hit my stride here toward the end of the season. Last year, I hit my stride at the end of the season, so I'm kind of hoping I follow that pattern."
Co-leader Miyazato, meanwhile, is enjoying a strong run at the moment, with five top-10 finishes to her name, though she's still searching for her first win of the year.
"My golf game is very confident right now," Miyazato said. "To begin the season, I was not so very good. I start to shoot right in the last couple four, five events. I'm gaining more confidence."
Elsewhere, World No 1 Yani Tseng shot a 70 and is five shots back, while defending champion Suzann Pettersen had a 71 and Stacy Lewis a 73.
Michelle Wie opened with a 69.
golf365.com