The 16-year-old New Zealand amateur successfully defend her title Sunday, closing with a 6-under 64 on Sunday at Royal Mayfair for a five-stroke victory and her fourth win in professional events.
Last year at Vancouver Golf Club in British Columbia, the South Korean-born Ko became the youngest winner in LPGA Tour history at 15 years, 4 months. She also was the fifth amateur winner in tour history and the first since JoAnne Carner in the 1969 Burdine's Invitational.
Ko's other victories in professional events came last year in the New South Wales Open and this year in the New Zealand Women's Open.
Ko had a 15-under 265 total after opening with rounds of 65, 69 and 67.
A stroke behind Caroline Hedwall entering the final round, Ko birdied five of the first eight holes and reached 15 under with a birdie on the par-4 12th. She dropped a stroke on the par-4 13th, parred the next four and closed with a birdie on the par-4 18th.
France's Karine Icher was second after a 67.
Hedwall, the Swede coming off a record 5-0 performance last week in Colorado in the Solheim Cup in Europe's blowout victory over the United States, had a 71 to tie for third at 9 under with Brittany Lincicome (69).