South Korean SooBin Kim shot a 9-under 63 onThursday to leave defending champion and top-ranked Lydia Ko seven strokes behind at the Women's Australian Open.

Kim's bogey-free opening round came after starting on the 10th hole of The Grange's West course. She had a three-stroke clubhouse lead over American Casey Grice with most of the afternoon groups, including five-time champion Karrie Webb, on the course.

P.K. Kongkraphan of Thailand and South Korea's Jenny Shin shot 67.

Ko, who won last year's title at Royal Melbourne, bogeyed two holes on her first nine after starting on the 10th, but the New Zealander had three birdies on the back nine for her 70.