Thailand's Patty Tavatanakit carded a brilliant eight-under-par 64 to join compatriot Atthaya Thitikul in the lead after the opening round of the Honda LPGA Thailand on Thursday, with the pair ahead by a shot.
ANA Inspiration winner Patty, who captured her maiden major last month in her rookie year on Tour, rolled in the last of her nine birdies on the par-5 18th hole to surge ahead.
Hannah Green, runner-up in the HSBC Women's World Championship in Singapore last week, continued her excellent form with a six-under 66 to be the best-placed Australian.
Green had a bogey-free round to take a share of fifth place.
South Korea's Kim Hyo-joo, who beat Green in Singapore as the LPGA returned to Asia for the first time in 18 months, was tied for 54th place after a disappointing round of 73.