Lydia Ko has blown the field away to win a second straight Canadian Open and waltzed to her fourth professional golfing victory.



The 16-year-old amateur, who won the tournament last year by three shots, bettered that this time with a five-shot victory at Edmonton's Royal Mayfair course.

More: Hole-by-hole breakdown of Lydia Ko's back nine



Her final round 64 was easily the low round of the day and she ended the tournament at 15-under. Asked if her final round was the best of her young career, Ko quickly pointed out she'd gone better.



''Well I shot 10-under at the Australian Open earlier this year, but today I was in a little bit of a pressure position,'' she said.



''So I was really happy with my 64. I got off to a really good start so that really helped my game.''



She'd barely signed her card and hadn't yet been awarded the Canadian Open trophy when she faced the familiar question of when she intended to turn professional and if this win would change her plan.



''I've always said I was thinking about it, it's the same answer right now. Nothing's changed in the last 72 hours. I'm happy at the moment and I think this win will make us think a little better and make us think what is a good option right now.''



Ko's dominance in the final round quickly forced her nearest competitors to focus only on the US$300,000 (NZ$383,926) winner's cheque that Ko can not claim at the NZ$2.55m tournament.



France's Karine Icher ended up second and took the big cheque courtesy of her final round 67 - the next closest day-four score to Ko's.



In 14 LPGA tournaments, Ko has made the cut in every one and missed out on an estimated US$970,000 (NZ$1,241,362) by remaining an amateur.



While it seems an odd decision by many that Ko does not opt to play as a professional, money won't be an issue when she does turn pro. She is expected to be courted by numerous sponsors and sign endorsement deals worth in the millions.