Stacy Lewis shot a 9-under 63 in the first round Thursday to take a three-stroke lead at the LPGA Thailand.
The American had an eagle on the par-4 third hole and added four more birdies on the front nine at the Siam Country Club Pattaya Old Course. She had two more birdies before a bogey at No. 16.
The 2012 LPGA Tour player of the year birdied the last two holes to finish three strokes ahead of Karine Icher (66).
"I really started hitting the ball solid early on. Holed out for eagle on No. 3 and from there, I don't know, that shot just really gave me the confidence to really start swinging at it," said Lewis, a six-time LPGA winner, including the 2011 Kraft Nabisco major. "I think I missed two greens all day. I just had a ton of birdie putts and I even left a few out there."
Inbee Park, Amy Yang, Catriona Matthew and Gerina Piller were four strokes behind. Top-ranked Yani Tseng was well off the pace at 3 over after a round with five bogeys.
Lewis said she left two birdie putts a half-roll short before she made an eagle on the third hole.
"I was a little frustrated going to No. 3," she said. "I think I had about 145 to the pin and I hit an 8-iron. It landed a few feet short and all the fans' hands went up, so I knew it went in. I guess it was just perfect."
Icher had a bogey-free round, marking a vast improvement on her final round at the Australian Women's Open last week in which she shot a 75 to finish tied for 55th.
"Last week I played really well, but I missed all of the putts," Icher said. "I'm happy because I improved my putting today, and it's a good sign for the rest of the season."