Ochoa, Cristie Kerr, Park Hee-young and Angela Stanford each shot 4-under-par 68 on the Garden Course at Singapore's Merah Country Club.
Ochoa had an early birdie at the second hole and three birdies over the four-hole span of Nos. 8-11 before she dropped strokes at Nos. 12 and 14. Birdies at 16 and 17 got her back to 4-under.
Park's round was even more up-and-down. She played Nos. 8-13 at even but that was because she countered three bogeys with three birdies.
Kerr was 2-over after three holes and was still 1-over after 12 holes before consecutive birdies on 13-16 and a closing-hole birdie got her a share of the lead.
Stanford shot a relatively tame bogey-free round. Her birdies came at 7, 9, 12 and 16.