Cherry Hills Village, Colo. ? She gave herself the nickname “Birdie” to distinguish herself from the other women on the LPGA Tour.

All it took was one shot – one spectacular birdie from the bunker – to make Birdie Kim a most unlikely U.S. Women’s Open champion Sunday.

Going shot-for-shot with 17-year-old Morgan Pressel at Cherry Hills, the 23-year-old South Korean was trying to get close for par when she holed a 30-yard bunker shot from across the 18th green, raising her arms as the ball disappeared in the back of the cup.

Pressel, poised to become the youngest major champion in golf history, was walking up the fairway in the group behind when she saw the reaction of the record gallery. She put both hands over her head in disbelief, realizing her dream of winning was all but gone.

“It was like, ‘I can’t believe that actually just happened,”‘ Pressel said when asked for her reaction.

In two years on the LPGA Tour, Kim had made 10 cuts in 34 starts and only once had finished in the top 10. Her career earnings were a meager $79,832. Kim finished at 3-over 287 and earned $560,000, the biggest payoff in women’s golf.

She closed with a 1-over 72 to win by two shots over a pair of teenage amateurs – Pressel, who went for broke on her birdie chip at the 18th and made bogey for a 75; and 19-year-old Brittany Lang, who missed an eight-foot par putt on the final hole for a 71.

Kim made the only birdie on the 18th hole in two days, a 459-yard par 4 that requires a daunting tee shot over water and an uphill climb the final 180 yards.

“I can’t believe it,” she said. “I don’t think I was going to make it. I was trying my best to make par.”

Annika Sorenstam, the dominant player in golf, never was a factor. She tried to drive the first green and instead hit a tree and went into the creek, making bogey. She wound up with a 77 to finish at 12-over 296, the first time in four years Sorenstam shot over par in a 72-hole event.

“Just didn’t happen,” she said.