“She made an amazing leap in the golf world at that Open, but for Jenny, it’s never been all about golf,” said Candy Hannemann, a former college teammate at Duke. “The joy of playing golf was why Jenny was so good, and when you take that away, it wasn’t fun anymore.”

That joy was evident in a famous photograph of Chuasiriporn, who had yet to begin her senior year at college, covering her mouth in amazement after she drained a 40-foot, twice-breaking putt for birdie on the 72nd hole to force the playoff at the Open.

She was wearing a Duke golf shirt with her older brother, Joey, carrying her bag. Her parents and her younger brother, Jimmy, along with friends and teammates from both her college team and the United States Curtis Cup squad, were in the gallery.

By contrast, Pak was a rookie phenom decked out in corporate logos. She had already won the L.P.G.A. Championship that year and had a multimillion-dollar endorsement deal with Samsung.

“I had very little expectation going into it, nor did I ever dream of finishing where I did,” Chuasiriporn said. “But I think she had a lot of pressure to win that golf tournament and to beat an amateur.”

Chuasiriporn birdied three of her first five holes in the Monday playoff, but her tee shot on the sixth hole found the deep rough, and she ended up with a triple-bogey 6 that brought her back in reach of Pak. They were even after 18 holes, forcing a sudden-death playoff that ended two holes later when Pak made a 15-foot birdie putt.