Updated

San Francisco, CA (SportsNetwork.com) - Lydia Ko birdied the 18th hole Sunday, completing a 3-under 69 to beat Stacy Lewis and win the inaugural Swinging Skirts LPGA Classic.

Ko, 17, collected her third career win on the LPGA Tour, but first as a professional, at 12-under 276. She won the CN Canadian Open in 2012 and 2013 as an amateur.

Lewis, who held the third-round lead, managed just a 1-under 71 Sunday at Lake Merced Golf Club to finish in second place at 11-under 277.

"When I see her play, it just makes me feel like I need to play good to kind of keep up with her. She's such a great player and I admire her all the way," Ko said about Lewis, whom she was paired with for all four rounds. "Someday I want to become a great player like her."

Jenny Shin (68) took third at 10-under, while world No. 1 Inbee Park (68), Line Vedel (69) and Shanshan Feng (70) shared fourth at minus-6. Hyo Joo Kim (70) and P.K. Kongkraphan (72) tied for seventh at 4-under 284.

Lewis started the final round with a 1-stroke lead and opened with nine straight pars to remain at 10-under.

Ko had a more adventurous front nine, making a bogey at the fourth to hand Lewis a 2-stroke lead.

She bounced back with a birdie at the sixth, and traded a bogey at the seventh with a birdie at the eighth to remain at 9-under.

Ko made it two gains in a row at the ninth to meet Lewis atop the leaderboard, and the duo both bogeyed the 10th to remain tied at minus-9.

A 2-shot swing at the 13th put Ko in the lead for good. She birdied the hole to move to 10-under and Lewis failed to convert a par putt from about 10 feet to fall to minus-8 and into a tie for second with Shin.

Shin was also playing in the final group with Lewis and Ko, and had countered a bogey at the seventh with birdies at the first, eighth and 11th holes to reach 8-under.

Ko, Lewis and Shin all birdied the 14th before Lewis added another gain at the 16th to pull within one of Ko.

Lewis had a chance to earn a share of the lead with a lengthy birdie putt at the 17th, but couldn't convert. Shin was able to roll in her birdie putt from about 10 feet at the 17th to meet Lewis at 10-under.

All three players found the green with their third shot at the par-5 18th.

After Shin failed to make her birdie effort, Ko put the tournament away with a birdie from about seven feet.

"It was just intense the whole way," Ko said about the final round. "At one point I had a 2-shot lead, but then Stacy made a birdie and Jenny made a birdie. At the 18th hole I knew how loud the claps were, so I knew I needed to hit it close and give myself a birdie opportunity."

Lewis converted her short birdie putt to take sole possession of second place.

"I knew it was going to be tough today. I knew (Ko) wasn't going to go away and Lydia played great. She answered every time I hit a shot in there," said Lewis. "More credit to her. I did all I could there. I made three birdies coming in and made her work for it at least."

NOTES: With the win, Ko is projected to move to No. 2 in Monday's world rankings ... Ko was named one of Time magazine's 100 most influential people on Thursday ... Dewi Claire Schreefel had a hole-in-one at the 12th. She won $100,000 with the ace ... Jimin Kang also posted a hole-in-one at the third ... Lewis will move into the top spot of the Race to the CME Globe standings.