LPGA's first major of the season went to sudden death after a TV viewer phoned in a 4-stroke penalty on the leader

NBC

Late in the final round of the LPGA's first major of the season, Lexi Thompson was seemingly cruising to her second major championship. But then the unthinkable happened when a TV viewer phoned in a 4-stroke penalty that cost her the win.

With six holes to go, Thompson had a three-stroke lead. However, what she didn't know was that the LPGA had received a phone call from a television viewer informing them of a potential rules violation late in Saturday's third round.

It turns out that Thompson incorrectly replaced her ball on a short putt on the 17th hole. Here is the infraction in question. According to the LPGA rules officials, you can't see the coin when the ball is marked, but when the ball is placed back on the ground, the coin is visible.

After a lengthy deliberation, the LPGA assessed two two-stroke penalties to Thompson. One of the penalties was for not playing the ball from the correct spot. The second penalty was for filing an incorrect scorecard.

Just as the television audience was being informed of the penalties, Thompson bogeyed the 12th hole. That meant her three-stroke lead, combined with the bogey and the penalties, dropped her to two strokes back with six to go.

Following the 12th hole, Thompson was informed of the penalties. She simply responded, "is this a joke?"

It was not.

Thompson was still trailing by one stroke when she approached the 18th green.

The crowd started chanting her name and she gave some in the gallery high-fives. She was visibly shaken and had to wipe away the tears.

She ultimately was able to work her way back to a tie with So Yeon Ryu and a sudden-death playoff. But it sure seems like the final few holes should have just been a victory lap for Thompson.