(REUTERS) - 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 US$1.6 million (S$2.1 million) Honda LPGA Thailand on Thursday (May 6), 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-five 18th hole to surge ahead.

The only blip for the 21-year-old on a sweltering day at the Siam Country Club in Chon Buri was a double-bogey on the sixth hole of the Pattaya Old Course.

"It was a solid round today. I didn't expect to shoot this low, I wasn't feeling my best," she said.

Atthaya also excelled in the heat with two eagles - on the 10th and the final hole - to stay in contention for her first title on the LPGA Tour.

"Today it was so hot but I just tried to keep my momentum going, keep rolling the putts," said Atthaya, who also shot five birdies.

"I gave myself a lot of chances to make birdies, if I made them that's good, if not just continue. I'm used to the heat but I don't know the course that well."

Another local favourite Ariya Jutanugarn, a two-time Major winner, was tied-third alongside Denmark's Nanna Koerstz Madsen after hitting 65 - a double-bogey on the 18th ruining her chances of joining the pair at the top.

South Korea's Kim Hyo-joo, who won last week's HSBC Women's World Championship 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.