Tavatanakit shot a bogey-free, 6-under-par 66 at Mission Hills Country Club’s Dinah Shore Tournament Course. She sits one stroke ahead of Ireland’s Leona Maguire and China’s Shanshan Feng.
Megan Khang, Sweden’s Anna Nordqvist and Thailand sisters Moriya Jutanugarn and Ariya Jutanugarn share fourth place at 68.
Jessica Korda, Jennifer Kupcho, South Korea’s Jin Young Ko and Mirim Lee, the Philippines’ Yuka Saso and three English players – Georgia Hall, Charley Hull and Bronte Law – are tied for eighth at 69.
Tavatanakit, in her second full season on the LPGA Tour out of UCLA, has three career top-10 finishes but no wins. Her best results were a tie for fifth in the 2018 US Women’s Open (her only event on tour that year) and a tie for fifth in the Gainbridge LPGA last month.
She started modestly Thursday, making two birdies through the first 12 holes, before running off three consecutive birdies on Nos 13-15 and adding another at No 18.
“Basically, it’s still my rookie year so there is a lot to learn,” she said following her round. “Everyone is good out here, so you have to show a lot of respect to the other players, too.
“It’s not like, oh yeah, I dominate the course. I still have to execute. I still have to hit good shots. I still have to play smart. I can’t ever get ahead of myself out there because literally anyone could shoot low numbers and sneak up there really quickly.”
Tavatanakit added about competing with more experienced foes, “Not every day is going to go your way. But I feel like the growth from being in contention will pay off. I just have to keep learning, keep being in it. Eventually I’ll be able to finish it out.
“It doesn’t have to be this week. I have a long career ahead of me, and I’m just going to keep playing the way I’m playing.”
Maguire, 26, opened with back-to-back birdies before bogeying the third hole. She had four birdies and 11 pars the rest of the way. Like Tavatanakit, Maguire was an LPGA Tour rookie last year, and she is also seeking her first victory.
Feng, 31, completed a bogey-free round. She owns 10 career LPGA Tour wins, including one major, the 2012 Wegmans LPGA Championship.