Carnoustie - Defending champion Jordan Spieth said a "brain fart" cost him a double bogey on the 15th hole and took the wind out of his sails in the first round of the Open Championship on Thursday.
The 24-year-old American - bidding to become the first player to successfully defend the Claret Jug since Irishman Padraig Harrington in 2008 - went to the 15th tee at three under par.
However, by the time he walked off the 18th at Carnoustie he was signing for a one-over-par 72 to lie six shots off clubhouse leader Kevin Kisner, one of his housemates for the week.
Spieth, who has not won since his victory at Royal Birkdale last July, ruefully admitted he had missed an opportunity to throw down an early gauntlet.
"Yeah, it felt like a missed opportunity," said Spieth.
"I felt like I was really going well. I had a nice par save after driving it in the bunker on six.
"Other than that, it was very stress-free. It was just a clean round of golf. I've done a bit of that this year, just the decision making that's cost me."
Spieth, who charged through the pack on the final day of this year's Masters with a sublime 64 to finish in third, said it was frustrating as he had committed the same errors which have plagued his game this season.
"The misses towards the end were the exact misses that I've been having and I'm working away from," said Spieth.
"The problem was on the second shot (at the 15th) I should have hit enough club to reach the front of the green, and even if it goes 20 yards over the green, it's an easy up-and-down.
"That's what I would consider as significant advantage for me is recognising where the misses are, and I just had a brain fart, and I missed it into the location where the only pot bunker where I could actually get in trouble, and it plugged deep into it.
"It was a really, really poor decision on the second shot, and that cost me."
However, the 2015 Masters champion -- one of a swathe of young Americans who hold all the major titles -- said with the weather set to turn nasty he isn't in the mood to surrender the Claret Jug yet.
"I think I'm certainly in a recoverable situation. I mean, I imagine this is as easy as the course could play.
"So I don't see the winning score being any better than it was in 2007 (seven-under, the last time it was played at Carnoustie) with tomorrow's forecasted tough conditions and Sunday's forecasted heavy winds.
"I think wherever it is Saturday night, it comes back on Sunday too.
"So it's not a bad place to be. You know, a solid round tomorrow to stay in the top 25, top 20 will be kind of the goal tomorrow to feel like I can do something on the weekend."