England's Jodi Ewart Shadoff carded an eight-under 64 to open up a two-shot lead after the opening round of the LPGA Mediheal Championship in California.
The 34-year-old from Northallerton, who is looking for her maiden LPGA victory, began with a birdie on the 10th and eagled the 14th before back-to-back birdies from the 17th saw her reach the turn in 31.
Ewart Shadoff responded to her lone bogey of the day at the par-four first by making four straight birdies from the fifth at The Saticoy Club as she jumped ahead of closest challengers Alison Lee and Ruixin Liu.
"I just felt really relaxed today," Ewart Shadoff said. "Everything was just kind of flowing. I was just rolling it really well with the putter. It helps when everything is just gelling together."
Liu mixed seven birdies with a lone bogey to post a six-under 66 and share second with Lee, who made a bogey-free start to the week, while Danielle Kang is in tied-fourth alongside South Africa's Paula Reto and Thailand's Atthaya Thitikul.
"I feel like I was hitting it really good all day today," Lee said. "I feel like I pretty much hit all my shots in makeable birdie range. I could have made a lot more.... I just feel like I played really awesome today.
"I would say it's not a super-easy course. It felt easy today obviously because I played so well. Other than that, you definitely need to think a little bit when you hit your approach shots and really need to keep in mind where the pin is and where the slopes are."
Northern Ireland's Stephanie Meadow opened with a four-under 68 and England's Georgia Hall recorded a one-under 71, while defending champion Matilda Castren is tied for 71st after a one-over 73.
Watch the LPGA Mediheal Championship throughout the week live on Sky Sports. Live coverage continues Friday from 10.30pm via the red button on Sky Sports Golf and - for free - on the Sky Sports Golf YouTube channel.