Rory McIlroy has caused a sensation by walking out of a tournament after eight disastrous holes, first blaming his mental state, and later revising it to a toothache.
The unprecedented meltdown for the world number one has raised serious questions about his new Nike clubs, which McIlroy changed to when he signed a €200m deal with the sports giant.
The two-time major winner left the course while playing the ninth hole of his second round at the prestigious Honda Classic at PGA National in Florida. He was seven-over par for eight holes and at times hit the ball like an amateur.
As he left the course, the Co Down man told awaiting reporters: "There's not really much I can say, guys, I'm not in a good place mentally."
The 23-year-old was then asked if anything was wrong physically. "No," he answered.
Caddy JP Fitzgerald confirmed his employer was not injured. When quizzed about his swing being faulty, McIlroy replied: "Yeah, I really don't know what's going on."
Later McIlroy cited severe toothache as the reason for his abrupt withdrawal and issued an apology to the tournament organisers and the PGA Tour.
In a statement he said: "I sincerely apologise to the Honda Classic and PGA Tour for my sudden withdrawal.
"I have been suffering with a sore wisdom tooth, which is due to come out in the near future. It began bothering me again last night, so I relieved it with Advil. It was very painful again this morning, and I was simply unable to concentrate.
Shortly before his walkout, he was seen happily munching a sandwich with no obvious signs of tooth pain.
His behaviour was all the more infuriating for tournament organisers, given that McIlroy was the defending champion at the Honda Classic.
The PGA Tour is now set to fine McIlroy $30,000 (€22,860).
McIlroy, from Holywood, Co Down, also tweeted later: "Apologies to all at the Honda. A tough day made impossible by severe tooth pain. Was desperate to defend title but couldn't play on. Gutted."
He was already set to miss the cut before his premature departure, after a series of bogies and a double bogey which had tainted his even par from Thursday.
Rory quit after hitting his ball into water on the 18th, which was his ninth hole, leaving playing partners Ernie Els and Mark Wilson to play out on their own.
The world's No 1 player took a penalty drop, then played another shot on to the green before signalling to his caddie that they were leaving the course.
Reaction from media and fans ranged from outrage to sympathy and jokes.
McIlroy's skills have brought him two Major championships, the World No 1 ranking and millions in earnings, all in five full years on Tour.