The American had an eagle on the par-4 third hole, then 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 then birdied the last two holes to finish three strokes ahead of Karine Icher (66).
Inbee Park, Amy Yang, Catriona Matthew and Gerina Piller were four strokes behind in a tie for third. Top-ranked Yani Tseng was well off the pace at 3 over after a round with five bogeys.
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