SHIMA, Japan - Sun-Ju Ahn won the Toto Japan Classic on Sunday for her first LPGA Tour victory and 20th Japan LPGA title, beating fellow South Korean player Ji-Hee Lee and American Angela Stanford with a birdie on the first hole of a playoff.
Ahn hit a 6-iron from 165 yards to 5 feet on the par-4 18th to set up the winning putt.
''I'm very happy,'' Ahn said. ''I didn't think that I'd be able to win the tournament, but it's a nice surprise. I'm very happy.''
Lee left a 50-footer short, and Stanford missed from 33 feet.
''About halfway I thought it might have a chance, but it broke more than I thought it would,'' Stanford explained. ''Sun-Ju hit a really good shot in there. If you stick it on 18, with this hole, you deserve birdie and you deserve to win.''
The 28-year-old Ahn closed with a 5-under 67 at Kintetsu Kashikojima to match Stanford and Lee at 16-under 200. Stanford also shot 67, and Lee had a 66.
Ahn has an option to take LPGA Tour membership next season and is eligible for the season-ending CME Group Tour Championship.
''I haven't thought much about that yet,'' Ahn said. ''I'm just going to enjoy this win and this moment.''
Ahn is projected to jump from 29th to 22nd in the world ranking. She also won the Japanese tour's Century 21 Ladies in July, and had seven career Korea LPGA victories.
The 37-year-old Stanford won the last of her five LPGA Tour titles in 2012. She dropped to 1-4 in playoffs, including a loss in the 2003 U.S. Women's Open.
She played the first two Asian Swing events in Malaysia and South Korea, then skipped the stops in Taiwan and China.
''When I left Korea I was pretty upset because I played bad in Malaysia and Korea,'' Stanford said. ''I went home put my head down and wanted to get better. I'm happy with this week.''
South Korea's Jenny Shin, the second-round leader, had a 70 to finish a stroke back.
Thailand's Ariya Jutanugarn closed with a 64 - the best round of the week - to finish fifth at 14 under. She began the day tied for 29th.
Third-ranked Stacy Lewis and No. 4 Lexi Thompson topped the group at 12 under. Lewis shot a 68, and Thompson had a 69. Thompson won three weeks ago in South Korea for her second victory of the year.
Michelle Wie tied for 59th at 2 under after a 71. She was one of 21 women to play in all five events on the Asian Swing.