Ochoa, who matched the course record Friday with a 7-under 65, was done in Saturday with a double- bogey six at the eighth hole.
"I made lots of birdies and I'm really happy for today," said Tseng. "I'm still in position and I'm just really looking forward for tomorrow and making some birdies."
Se Ri Pak and Song-Hee Kim both shot rounds of three-under 69 Saturday and are tied for fifth place at 5-under 139. Sun Young Yoo (70), Grace Park (71) and Suzann Pettersen (71) are tied for seventh at 140.