Golf: Ko wins US amateur tournament

New Zealand golfer Lydia Ko, 15, has lived up to her No.1 world amateur ranking by winning the final of the US amateur women's championship in Ohio.

The Aucklander beat 18-year-old American Jaye Marie Green 3 and 1 at The Country Club course in Cleveland.

Ko was two up on the 16th and won the par four 17th to go 3 up and take the title.

It was a commanding performance by the New Zealander, she led from the start and at one stage was 4 up.

Ko won the NSW Open in January at age 14 to become the youngest player to win a professional tour event.