INCHEON, October 20, 2013 (AFP) - Yang won the first extra hole to defeat fellow South Korean Seo Hee-Kyung on the par-72 Ocean Course at Sky72 Golf Club in Incheon, west of Seoul.
Yang and Seo were tied at nine-under 207 in the 54-hole, $1.9-million event. Both birdied the par-5 18th to get into the playoff.
Yang teed off first on the first playoff hole, the 18th, and found deep rough right of the fairway. She chopped out before hitting her third shot to around 16 feet from the hole.
Seo found left rough from the tee and also had to chip out of harm's way to set up her third shot, which finished almost 25 feet below the pin.
Seo's birdie attempt grazed the left edge of the cup before rolling a few centimetres past. Yang then stepped up to drain the putt to clinch the win.
Yang had previously won three times on the Ladies European Tour and once on the Korean LPGA Tour.
This was Yang's 119th US LPGA start. She said at a press conference that her victory had been a long time coming.
"I am especially happy that I got my first win in my home country," she said. "It hasn't hit me yet. I don't think I will be able to sleep tonight."
Yang said she played the final round with confidence because of how she'd been hitting her shots of late, and credited her hot putter for getting her over the hump on Sunday.
She also admitted she thought about quitting golf but a new approach to the sport helped her turn things around.
"I used to go all out in practices, hitting shots until dusk without taking breaks," she said. "But I decided to take a step back and look at the world around me. I also started to take some time off and I gradually got better."
This was the second straight year that the only US LPGA event in South Korea ended in a playoff. Last year, Suzann Pettersen defeated Catriona Matthew on the third playoff hole.
Yang began the day at six-under, one shot behind the co-leaders Anna Nordqvist and Katherine Hull-Kirk.
Yang had a steady front nine with one birdie, and after committing her only bogey of the day at par-4 11th, she made some noise with an eagle on the par-4 15th.
She then birdied the 18th to enter the playoff.
Seo, the 2011 US LPGA Rookie of the Year, also birdied the 18th to set up the sudden-death battle with Yang, but came up shy of earning her second US LPGA victory.
American Michelle Wie shot a blistering six-under 66 on Sunday to finish in a three-way tie for second at eight-under 208.
World number two Pettersen joined her after shooting a two-under 70. Kim Sei-Young, currently leading the KLPGA Tour money list, also tied for second.
Nordqvist stumbled to a 75 to end in a tie for eighth along with four others. Hull-Kirk collapsed with a round of 80 and finished tied for 32nd.
Leading scores after the final round of the $1.9 million LPGA KEB-HanaBank Championship on Sunday (par 72, 54 holes)
(*denotes playoff winner)
207 - * Amy Yang (KOR) 67-71-69, Seo Hee-Kyung (KOR) 71-68-68
208 - Michelle Wie (USA) 69-73-66, Kim Sei-Young (KOR) 71-68-69, Suzann Pettersen (NOR) 69-69 70
210 - Kim Ha-Neul (KOR) 69-70-71
211 - Brittany Lincicome (USA) 71-71-69
212 - Jane Park (USA) 70-72-70, Pak Se-Ri (KOR) 73-68-71, Shin Ji-Yai (KOR) 69-71-72, Anna Nordqvist (SWE) 67-70-75
213 - Jodi Ewart Shadoff (ENG) 71-72-70, Ji Eun-Hee (KOR) 71-72-70, Caroline Hedwall (SWE) 68-74-71, Chella Choi (KOR), 73-68-72, Park Ju-Young (KOR) 67-71-75