Tseng has won two of the four tournaments in which she has played this season, including last week's Founders Cup -- the LPGA Tour's first event of the year in the United States.
She shot a 5-under 67 at the La Costa Resort and Spa to tie Ji Young Oh and Caroline Hedwall for first place.
Tseng began play on the back nine and after she made the turn she birdied the first, second and third. Her only bogey came at the par-3 eighth.
Iranian woman stops the execution of son's killer
Members of Congress to keep receiving porn magazine