Brittany Lang secured her first career major at the US Women's Open after Anna Nordqvist was handed a two-stroke penalty for grounding her club during the play-off.

The 29-year-old Swede touched the sand with her club in a bunker during a three-hole aggregate play-off, effectively handing the title to Lang.

The penalty occurred on the second hole of the play-off but the players were not informed until they were on the final hole after USGA officials viewed TV replays.

Lang completed victory with par on the final hole, with Nordqvist recording a bogey to lose by three strokes.

"Well, I was in the fairway bunker there on 17. It was blowing 35, 40, and I had a 5-iron, downhill lie. Just focusing on hitting my shots, and apparently I touched the sand. It wasn't on purpose. And just one of those things," Nordqvist said.

"I have to deal with the consequences. Unfortunately it happened, but it's not the end of the world.

"I wish USGA would have told me a little bit earlier - they approached me after I already hit my third shot into 18, then kind of ran up to Brittany to tell her that I got penalised. I don't know if it would have changed the outcome, but it certainly would have changed my aggressiveness into the 18th pin."

Lang shot a one-under 71 to finish with a six-under total of 282 for the tournament in San Martin, California.

Nordqvist's superb five-under round of 67 moved her into contention as overnight leader and world number one Lydia Ko dropped back with a three-over 75 to finish in a tie for third with Amy Yang, Eun-He Ji and Sung Hyun Park on four under.

England's Jodi Ewart Shadoff closed with a two-under 70 to finish in a tie for eighth place on two under while Scotland's Catriona Matthew shared 26th on 290.