Tseng had birdies over Nos. 13-15 in shooting a 5-under-par 67 for a 54-hole total of 10-under 206. She has a two-stroke lead over Anna Nordqvist, who shot 1-under 71 Saturday and is at 8-under for the tournament.
Azahara Munoz, who was tied with Nordqvist for the lead after two rounds, had an even-par 72 Saturday and is three strokes off Tseng's lead. Han Hee-won and Amy Yang, who both shot 70 Saturday, are tied for fourth at 6-under.
Han and Yang had the low scores of the day outside of Tseng's 67.
Tseng had a birdie on the par-3 second hole but slipped back with a bogey at the par-3 fourth. She carded birdies on Nos. 5, 7 and 9 and made the turn at 3-under.
She had another bogey at 11 -- another par 3 -- but then ran off her string of three consecutive birdies to pull clear. She closed the day with three pars.