Ryu So-yeon clinched her second major title after a drama-filled play-off win over Lexi Thompson at the ANA Inspiration.

Thompson was sensationally handed a four-stroke penalty late in her final round on Sunday for an incident a day earlier.

The American, clearly emotional after receiving the news between holes 12 and 13, recovered to card a five-under 67 and finish at 14 under at Mission Hills Country Club.

Thompson had an eagle putt for victory on the 72nd hole but it was short, seeing her finish alongside Ryu (68).

After Thompson missed the fairway off the tee on the first play-off hole, Ryu held the upper-hand and she claimed her win with a birdie.

The win marked Ryu's second major crown and first since she took out the 2011 U.S. Women's Open.

Fans were undoubtedly behind an emotional Thompson, the 2014 champion penalised after a TV viewer emailed the LPGA.

It was ruled the 22-year-old played from the wrong place on the 17th hole in her third round, leading to a two-shot penalty.

She incurred an additional two-stroke penalty for returning an incorrect scorecard.

A gutsy Thompson steadied, making birdies at 13, 15 and 18, and a bogey at 16, to force the play-off.

But her wayward tee shot, and the penalty, would prove decisive as Ryu closed out victory.

Suzann Pettersen (70) fell just short of the play-off and tied for third at 13 under along with Park Inbee and Minjee Lee.