With the 18th pin and a championship in sight, Lydia Ko found herself in the rough again in a day filled with off-target drives. The teen told herself she just needed one more important chip with the tournament on the line.

Poised and unflappable, Ko made the perfect pitch up to the green and birdied the final hole for her first LPGA Tour victory as a professional and third in all, holding off Stacy Lewis and Jenny Shin on Sunday in the inaugural Swinging Skirts LPGA Classic.

In one memorable week, Ko turned 17, earned a spot as one of the 100 most influential people in the world by TIME magazine and captured her first LPGA Tour win as a pro -- all while playing with a fill-in caddie from the local club.

"Normally they would say sweet 16, but I would say it's sweet 17," Ko said. "I don't think I could have any better birthday week."

It went down to the final shots, and the teen made a 6-foot birdie putt moments before Lewis knocked in a 4-footer of her own to finish one stroke back.

After beginning the day a stroke behind Lewis, Ko birdied three of her final four holes on the front nine on the way to a 3-under-par 69 and 12-under 276 total at Lake Merced.

Ko earned $270,000, celebrating on the 18th green three days after celebrating her birthday at the first tee box with the gallery singing "Happy Birthday."

Ko, born in South Korea and raised in New Zealand, will move up two spots to No. 2 in the next world ranking.

Her father, G.H., got to see her win Sunday.

"Tears nearly ran down my face. You may lose friends but you're always going to have your parents," Ko said. "I try to make myself not cry of happiness but it was coming to that point."

She won the Canadian Women's Open as an amateur the last two years and took the Swinging Skirts World Ladies Masters in December in Thailand in her second start as a professional. She has six victories in pro events, also winning in Australia and New Zealand.

All three of Ko's LPGA wins have come on courses most of the other golfers also played for the first time.

The third-ranked Lewis finished with a 71 for her sixth runner-up finish since winning the Women's British Open in August. She will head to her home state of Texas next week looking to build on a disappointing near miss in which she struggled all day with her short game.

"I knew she wasn't going away. Lydia played great," Lewis said. "Every time I hit a shot in there, she answered."

Shin, still looking for her first tour win after her best finish this year, had a 68 to finish two shots behind.

"They were fearless," Shin said about her playing partners, "They just went for it."

Playing together for the fourth straight day, neither Ko nor Lewis hit any dazzling shots early. Ko's second of three bogeys came on the 417-yard, par-4 seventh in which her tee shot hit a tree and dropped in the rough. Lewis' 10-foot birdie putt on No. 9 lipped out.

Ko pulled into a first-place tie at 10 under as they made the turn on a picture-perfect spring day, then took the lead with a birdie on No. 13. Lewis went in the bunker, missed the green and two-putted for bogey to fall two back.

"The front nine, I did everything I wanted to do, the putts just didn't go in," Lewis said. "I expected her to do exactly what she did today. . . . She hit every shot she needed to make from 13 on in."

There were two holes-in-one Sunday: Jimin Kang on the 164-yard third and Dewi Claire Schreefel with a 7-iron on the par-3, 157-yard 12th hole that earned her a $100,000 prize from China Trust Bank.

The weather held for the final day after fog and rain delays earlier in the tournament.

This event was the LPGA's first in the Bay Area since the 2010 CVS/pharmacy LPGA Challenge at Blackhawk in Danville.

Organizers and club officials are optimistic about keeping the tournament at Lake Merced.

Donna Lowe, Lake Merced general manager, hopes an announcement would come within a month to begin planning for 2015.

San Francisco Mayor Ed Lee has spoken with Swinging Skirts Chairman Johnson Wang, while Lowe has received positive feedback from LPGA Commissioner Michael Whan, players and their caddies.

"So far, it's just been amazing and very positive and uplifting," Lowe said of the feedback.

DIVOTS: Michelle Wie, who won last week in her home state of Hawaii, tied for ninth at 2 under. Second-ranked Suzann Pettersen shot a 70 finish at 3 over in her first event since last month after missing three tournaments with a back injury. Top-ranked Inbee Park tied for fourth at 6 under.