Rory McIlroy conceded that his error-strewn back nine during the third round of The Open had got to him after he snapped one of his clubs when throwing it to the ground in frustration.
The Northern Irishman's approach at the par-five 16th veered right and his angry reaction led to his three-wood breaking on impact with the fairway.
"I think it was just I let one go right on the previous hole, the three iron, and I did the exact same thing there," said the four-time major winner, who shot 73 on Saturday.
"So it was basically just a bad swing. No one likes to make the same mistake twice and that's basically what happened.
"I actually felt like I played okay on the back nine. Held it together quite well. I obviously had the bogey on 15 and actually had a decent chance on 16 to make birdie."
But he did not take full responsibility for the harm caused to his fairway wood, adding: "The club head came loose on it earlier in the week.
"I had to get the head re-glued. So it was probably partly to do with that and partly the throw as well.
"The truck's here, so I'll have it reshafted, and all will be well in the morning.
"But it was one of those days that was a tough day."
McIlroy won golf's oldest major in 2014, but was unable to defend his title at St Andrews last year after being ruled out by injury.
Phil Mickelson and Henrik Stenson are vying for the Claret Jug this year and appear unlikely to be troubled by the chasing pack.