EDMONTON, August 25, 2013 (AFP) - Ko, whose triumph in Vancouver last year at the age of 15 years and four months made her the youngest LPGA title winner in history, backed up that milestone victory with a five-stroke victory over France's Karine Icher.
On Sunday she became the first amateur ever to win two LPGA titles.
Ko, of Auckland, carded a final-round six-under 64 at Royal Mayfair Golf Club for a 15-under total of 265.
The bespectacled teen curled in a birdie putt at 18 -- her seventh birdie of the day -- lifting her arms in triumph as it dropped.
Icher, one of the bevy of Europeans playing this week in the wake of their Solheim Cup triumph over the United States in Colorado, carded a 67 for 270.
Sweden's Caroline Hedwall, the first player to go 5-0 in the Solheim Cup, had started the day with a one-stroke lead. She carded a 71 to share third on 271 alongside American Brittany Lincicome, who shot 69.
Ko's fourth victory in a professional tournament is bound to renew the question of when the 16-year-old phenom will turn professional.
She won the New Zealand Women's Open in February, a Ladies' European Tour event while her win at the age of 14 in the Australian LPGA's Women's New South Wales Open in January of 2012 had made her the youngest player male or female to win a pro tournament.
Leading final-round scores on Sunday in the US LPGA Canadian Women's Open (a-denotes amateur, USA unless noted, par 70):
265 - a-Lydia Ko (NZL) 65-69-67-64
270 - Karine Icher (FRA) 67-66-70-67
271 - Brittany Lincicome 68-68-66-69, Caroline Hedwall (SWE) 68-68-64-71
272 - Stacy Prammanasudh 68-67-69-68, I.K. Kim (KOR) 71-66-65-70
273 - Caroline Masson (GER) 70-67-67-69, Suzann Pettersen (NOR) 69-67-65-72
274 - Gerina Piller 70-66-67-71
275 - Jessica Korda 70-66-68-71, Jodi Ewart Shadoff (ENG) 71-66-67-71, Paula Creamer 66-68-69-72
276 - Mika Miyazato (JPN) 70-67-70-69, Angela Stanford 65-68-73-70, Park In-Bee (KOR) 67-65-74-70, Brittany Lang 70-67-68-71
277 - Choi Na-Yeon (KOR) 67-71-70-69, Catriona Matthew (SCO) 70-66-71-70, Charley Hull (ENG) 69-66-71-71
278 - Anna Nordqvist (SWE) 70-70-70-68, Ai Miyazato (JPN) 70-68-71-69, Cristie Kerr 66-66-75-71, Lexi Thompson 71-65-69-73
279 - Pernilla Lindberg (SWE) 70-69-72-68, Juli Inkster 69-72-69-69, Shin Ji-Yai (KOR) 74-66-67-72, Danielle Kang 71-67-69-72, Tseng Ya-ni (TPE) 72-68-66-73