The World No.3 played an outstanding bogey-free final round, and birdied the first playoff hole to snatch the first major of the season from a gallant Thompson, who was dramatically awarded a four-stroke penalty midway through her final round.

Thompson was cruising with a three-shot lead after 12 holes on Sunday when rules officials approached her on the 13th tee. A television viewer had emailed the LPGA saying the American had marked her ball then replaced it incorrectly before putting out on the 17th hole during her third round. And, after reviewing the footage, Thompson was incredibly awarded a four-shot penalty for the incident and for signing an incorrect scorecard. The 22-year-old was then forced to hit her tee shot through tears.

Lexi Thompson cries into a towel as she walks to the 18th green during the final round. PHOTO: Robert Laberge/Getty Images

But the World No.9 rallied, with birdies at two of the next three holes to reclaim the solo lead. A visibly shaken Thompson then hit an incredible second shot – a 190 yard 5-iron – into the par-5 18th to 12 feet. The eagle putt came up short by less than six inches, and the resulting birdie sent her to an unsuccessful playoff against Ryu.

“It’s unfortunate what happened … I did not mean it at all,” Thompson said greenside. “I learnt a lot about myself, and how much fight I have in me. I wasn’t expecting what happened to me today, but it is what it is, and I’ll learn from it.”

Support for Thompson among her playing peers was united in calling the four-stroke penalty, and its timing, unfair. PHOTO: Jeff Gross/Getty Images.

Tiger Woods was one of multiple players who were outraged by the decision, and expressed his displeasure via Twitter: “Viewers at home should not be officials wearing stripes … Let’s go Lexi, win this thing anyway.”

While Ryu was gracious in a victory that handed South Korea five of the last six tournaments on the LPGA Tour.

So Yeon Ryu takes the traditional plunge into Poppie's Pond. PHOTO: Jeff Gross/Getty Images.

“It doesn’t feel right and I can’t believe this situation,” Ryu said. “Every player is so dedicated and we always work hard to bring our A-game, so it hurts me as well … It’s kind of a weird feeling, but at the same time I’m very proud of myself.”

Australia’s Minjee Lee came close to claiming her first major championship, after finishing in a tie for third and only one shot off the lead. But bogies on both of the back nine’s par-3s hurt the 20-year-old, who eventually signed for a three under 69.