Tseng, who won the McDonald's LPGA Championship this year, completed 54 holes at 14-under 202. Earlier in the day, Tseng completed a round of 8-under 64 to take a share of the lead after two rounds.
The second round was completed Saturday morning after play was suspended Friday due to inclement weather.
Se Ri Pak moved into second place at 10-under 206 after a third-round 68.
A showdown between Lorena Ochoa and Annika Sorenstam fizzled in the third round when Ochoa turned in a 2-over 74 and Sorenstam wound up with a 4-over 76. Ochoa dropped from a share of the lead into a tie for third at 8-under-par 208 and Sorenstam dropped into a tie for 14th.