Lydia Ko has won her third Canadian Women's Open, beating world number three Stacy Lewis in a playoff.
Ko won the sudden-death playoff on the first hole, holing a three footer for par to defeat Lewis, who could only manage a bogey.
Ko began the day in a share of the lead and moved out to a two-shot lead following a birdie on the par three third. But the 18-year-old dropped a shot at the par four ninth to move back to 12-under.
She parred the back nine to end up firing an even-par 72, and joining the playoff with Lewis, who shot a 67.
Ko previously won the Open in 2012 at Vancouver Golf Club at 15 years, 4 months to become the LPGA Tour's youngest winner and fifth amateur champion. She successfully defended her title in 2013, also as an amateur, in Edmonton, Alberta.
"This feels amazing," Ko said. "I had an amazing week. ... To play good golf in front of great crowds was one of the highlights of this week. I feel somewhat Canadian."
"I said, 'Hey, you've just got to concentrate on your game, just one shot a time,' and that's what I tried to do," Ko said. "I said, 'I don't want to get too aggressive to that pin, but maybe it was a little bit too safe and maybe wasn't the best shot going in. I made a really good first putt on my normal 72nd hole, and made a good putt on the first playoff hole."
It is Ko's eighth LPGA Tour title, and third LPGA Tour win in 2015, having previously triumphed at the Swinging Skirts LPGA Classic in April and the Australian Women's Open in February. She also won the New Zealand Women's Open in March.
She now holds a perfect 3-0 record in playoffs.
Ko takes home $337,500 (US) for the win, moving her to over $1.7 million in earnings for the season - second on the LPGA Tour money list behind South Korea's world number one Inbee Park.