ANA Inspiration: Lexi Thompson 'still having nightmares' over 2017 event
World number two Lexi Thompson says she still has nightmares about the four-stroke penalty which cost her victory at last year's ANA Inspiration.
The American was left in tears after being handed the penalty while leading the final round of the first major of the season.
She went on to lose a play-off to Ryu So-yeon, though the incident prompted a rule change in the sport.
"That night was extremely rough," the 23-year-old said.
"I was screaming, crying. I had nightmares about it and I still occasionally do," she added.
Thompson was handed the penalty for putting her ball down in the wrong spot after marking it during the third round of the tournament.
However, the offence was only spotted by a TV viewer who got in touch with officials.
It meant she received a two-stroke penalty for 'playing from the wrong place' plus a further two-stroke penalty for returning an incorrect scorecard in round three.
Her five-under-par third-round 67 was changed to a 71.
Thompson had been leading the tournament by two shots when told of the penalty after her 12th hole on the fourth and final round the next day.
"It's been rough," Thompson told reporters before the 2018 ANA Inspiration, which gets under way at Rancho Mirage, California, on Thursday.
"I stayed off social media after that because media was blowing it up and making me feel terrible.
"I had to let it go and let time pass."
The rules were subsequently changed so that players can no longer be penalised by video evidence for things that "could not be seen with the naked eye".
Players are also no longer penalised for returning an incorrect scorecard if they were not aware the scorecard was wrong.
"I'm just happy the rule changed so nobody else can be put through what I was put through last year," Thompson said.