(Reuters) - American Brittany Lang won her first major title in dramatic fashion at the U.S. Women's Open on Sunday after her playoff opponent, Anna Nordqvist, was assessed a two-stroke penalty for grounding a club in a bunker.

Following a video review by United States Golf Association officials, Swede Nordqvist was penalized for her actions in a fairway bunker on the second extra hole, the par-four 17th, where her five-iron lightly grazed the sand on her takeaway.

According to rule 13-4b, a penalty is invoked if a club touches the sand in a bunker before the downswing, no matter how light the contact.

Nordqvist was informed about the penalty only after she had hit her third shot on the third extra hole, the par-five 18th, leaving the title up for grabs for Lang after both players had parred the first two holes.

Lang, whose only previous LPGA victory came at the 2012 Manulife Financial Classic, ended up winning the three-hole aggregate playoff after making three consecutive pars. Nordqvist finished at three-over after bogeying the 18th.

"It was definitely a shame for Anna for it to come down to something like that," Lang, 30, said after being presented with the gleaming silver Open trophy. "You never want it to be because of a penalty but to be because of better play.

"I am ecstatic, I feel for her but definitely it (the penalty) took a little bit of pressure off me. I can't believe it. It means absolutely everything. This is what you dream of. It's amazing."

Lang's win ended a run of four victories by South Korean players at the U.S. Women's Open over the past five years.

The duo finished regulation on six-under-par 282, Nordqvist firing a 67 while Lang closed with a four-birdie 71 at CordeValle Golf Club in the third of the year's five major championships.

Nordqvist, who won her first major title at the 2009 LPGA Championship, played superb bogey-free golf during the final round and sank an eight-foot eagle putt at the par-five 15th on her way to the early clubhouse lead.

The two-stroke penalty during the playoff came as a bitter blow.

"I didn't do it on purpose," said the 29-year-old Swede. "What can I say? I touched the sand so ... a penalty.

"I've played really good today but it's just hard to lose that way. I hit 17 greens today and missed one by two feet. I shot five under on a Sunday to give myself a chance so I am proud of myself."

New Zealander Lydia Ko, at 19 aiming to become the youngest golfer to win three major titles, had been two strokes clear with 12 holes to play but her round unraveled with a damaging double-bogey at the ninth.

The world number one carded a 75 to tie for third, two shots out of the playoff.

(Reporting by Mark Lamport-Stokes in Los Angeles; Editing by Andrew Both)