
After a bogey at her first hole, the American bagged seven birdies and an eagle to build a solid lead over the chasing pack, which was led by Yuka Saso on five-under after the Japanese world No 36 shot a flawless 67.
American world No 2 Nelly Korda carded a 68 for a share of third place with five other players, including fellow Major winners Patty Tavatanakit, Kim Hyo-joo, Ariya Jutanugarn and Lee Jeong-eun.
Top-ranked Lydia Ko (70) of New Zealand and South Korea’s reigning champion Ko Jin-young (72) endured difficult days with the putter at the Sentosa Golf Club and finished in a share of 14th and 36th respectively.