''I just cannot believe the situation,'' Ryu said after defeating Lexi Thompson with a birdie on the first hole of their sudden-death playoff. ''I didn't even check the leaderboard. I thought Lexi played really, really well. I didn't expect what happened to Lexi.
''It's a very unfortunate situation. I didn't expect it. I thought I'm well behind, so all I wanted to do was play my game.''
Ryu, who also won the 2011 U.S. Women’s Open in a playoff, was informed on the 16th tee that Thompson was being hit with a four-stroke penalty over an incident late in her third round.
A television viewer's email had alerted officials to a day-old rules violation by Thompson for a 1-inch ball placement error. Her three-shot lead had just been wiped out by a four-shot penalty.
Ryu birdied the par-5 18th hole to get to 14 under par, one stroke ahead of Thompson and Suzann Pettersen in the final group. Thompson matched Ryu’s birdie to get into the playoff, while Pettersen couldn’t get her short birdie putt to fall.
In the playoff, Ryu was just off the green in two and got up and down for birdie, while Thompson, who had driven into deep rough and had to lay up, missed her birdie effort.