Thai teenager Atthaya Thitikul was six shots behind leaders Ai Suzuki and Momoko Ueda after teeing off as world No 1 for the first time at the LPGA Japan Classic on Thursday.
Atthaya hit two birdies and a bogey on the way to an opening-round one-under-par 71 at Seta Golf Course in western Shiga Prefecture.
Suzuki and Ueda led fellow Japanese pair Ayaka Furue and Sakura Koiwai by one stroke as the LPGA returns to Japan for the first time since 2019.
The 19-year-old Atthaya is playing her first tournament since becoming the second-youngest world No 1 in women's golf history this week, following a stunning debut year on the LPGA tour.
Atthaya said her round was "so so" but believes she is capable of coming back to claim her third title on the LPGA this season.
"I can bounce back, with one-under it's good enough for me," she said.
"I learned today to be patient out there because I couldn't be aggressive that much, which means getting my driver on the fairway as well."
The LPGA is returning to Japan for the first time since the coronavirus pandemic for an event co-sanctioned with Japan's JLPGA.
The event was contested as a JLPGA-only event in 2020 and 2021.
"I think it's a good sign for us to have so many fans come out, all these little girls came out," said Atthaya.
"Since Covid, we haven't had much fans like this so I feel good seeing them come out and support us here."