Ja pan's Haru Nomura fired a closing seven-under-par 65 to deny defending champion and world No.1 Lydia Ko and win the LPGA-sanctioned Australian Open at The Grange in Adelaide on Sunday.

Nomura, 23, holed eight birdies in the final round having started the day in a three-way share of the lead at nine-under.

The Japanese player closed the door on Ko's chances with a monster 15-meter birdie putt at the 17th when she was three shots ahead of the New Zealand ace. It allowed Nomura the luxury of her only bogey at the par-four 18th when she found the front-right sand trap and failed to get up and down.

It was the 67th-ranked Nomura's first LPGA win after five seasons on the tour in America without drawing much attention.