Tseng, who was honored earlier this week for having wrapped up Player of the Year honors, had her only bogey of the day on the first hole. Miyazato had five birdies and a 16th-hole bogey en route to her 68 in windy conditions at the Sunrise Golf and Country Club.
Miyazato moved into the lead with four birdies over Nos. 5-9. She slipped back with the bogey at the par-3 16th hole but returned to 4-under with a birdie at the 18th.
Tseng, playing in her home country, took a bogey on the first hole partially attributed to the crush of fans. She came back with a birdie at the third hole and closed the front nine with birdies at 6, 8 and 9. She had eight consecutive pars on the back nine before a closing birdie at the par-5 18th won her a share of the lead.