So Yeon Ryu is the ANA Inspiration champion, but not before one of the most dramatic days in living memory on the LPGA Tour.

Ryu defeated Lexi Thompson with a birdie on the first hole of a sudden-death playoff at Rancho Mirage in California, but sadly the day will long be remembered for the imposition of a four-stroke penalty against the American after a TV viewer’s email.

It also detracted from Australian Minjee Lee’s brilliant tie for third, her best result at a major championship in her burgeoning career.

Thompson was informed of her penalty – for a clear error while marking and replacing her ball on the 17th green in yesterday’s third round – in the most extraordinary circumstances.

The buoyant 22-year-old was standing on the 13th tee after making a bogey on the 12th that seemingly left her still in command with a three-shot lead.

But two rules officials approached her and after an emotional exchange, she was docked two strokes for having played from the wrong position and two additional strokes for having signed for an incorrect score.

Remarkably, the now angry American wiped away tears and made a birdie on the 13th, then followed up on the 15th with another to retake the lead as a wave of support kicked in for her around the course.

Ultimately, though, a wayward drive on the 16th led to a testing bogey putt that slid agonisingly left of the hole almost as Ryu got up and down on the last to take the lead.

Ryu, whose support crew is predominantly Australian, played a spectacular bump and run on the final hole after her approach went to the foot of the grandstand behind the green.

The Korean chipped back down with a surgeon’s touch to inside 1.5m and calmly rolled in the birdie to reach the clubhouse lead at -14.

In the following group, Lee hit a cracking five-iron to the back fringe of the par five. But, knowing she needed an eagle to match Ryu, the West Australian’s bid turned agonisingly left in the last metre and she settled for a birdie.

Lee’s rounds of 70-68-68-69 gave her a -13 total and her T3 was her best major championship result at the tournament at which she was low amateur in 2014.

Seemingly willed on by a now raucous crowd in her corner, Thompson rifled her own great approach to the last, setting up an eagle try that would have sealed one of the great sporting stories of the year.

But that – and her birdie putt on the playoff hole – both fell short as Ryu again cashed in on another delicate third shot to seal victory.

Thompson, still with tears almost two hours after being notified of her infraction insisted she had not intentionally acted illegally.

“It’s unfortunate what happened – I did not mean that at all, I didn’t realise I did that,” she said.

“I just regrouped myself, my caddie helped me tremendously and just said, Stay with it, we can still win’. So I tried to gather myself before I hit that tee shot (on the 13th) and made a great putt there.

“I learnt a lot about myself and how much fight I do have in me. Every day is a learning process; I wasn’t expecting what happened today, but it is what it is and it happened and I’ll learn from it and hopefully do better.

“I’m proud, just the way I played coming in. I am a very emotional person and I fought strong and that’s all I can do.”

A gracious Ryu, 26, said she “could not believe the situation” having in her mind been playing for second place at the time.

“I didn’t expect what happened to Lexi and it was a very unfortunate situation,” said the Korean, now a dual major champion after her 2011 US Open triumph.

“All I thought was I was well behind and I just wanting to play my game and have a strong finish.

“It hurts me as well. It’s a weird feeling, but I’m proud of myself.”

Inbee Park and Suzanne Pettersen were alongside Lee at 13 under, the Norwegian having missed a 2m birdie putt on the last hole to join the playoff in the group with Thompson.

Asked of Thompson’s achievements, Pettersen was effusive in her praise even though it ultimately came up short.

“I thought she took it with the character she is … it’s true class for Lexi,” Pettersen said.

“When you get that right in the face after 12 holes, she played so well to make those birdies and … keep it all together.

“I’ve got goosebumps talking about it.”

Final results can be found at lpgascoring.com