CARNOUSTIE, Scotland — Through 14 holes, Jordan Spieth was challenging for the lead in the British Open and making it look easy.

"Just a clean round of golf," he said.

And then it got messy in a hurry.

Spieth came undone on the tough closing stretch at Carnoustie, dropping four shots over the final four holes. One shot went into the bunker. Another went into the Barry Burn. Another was closer to the gallery than the green.

He had to sign for a 1-over 72, the fifth time in his last seven majors that he was over par after the opening round.

What bothered Spieth was not so much a shot, but a decision.

His slide began on the 492-yard 15th hole, when he chose 4-iron off the tee and the ball bounced to the left on the crusty links into wispy fescue. That wasn't a problem. Spieth was 202 yards from the front of the green and decided to hit 6-iron that would land short of the green and roll onto the putting surface.

The risk was hitting into a pot bunker, and he found the worst one.

"Even if goes 20 yards over the green, it's an easy up-and-down," Spieth said. "And that's what I would consider a significant advantage for me is recognizing where the misses are. And I just had had a brain fart. I missed it into the ... only pot bunker where I could actually get in trouble. And it plugged deep into it."

The crowd knew he was in trouble when he turned to a 90-degree angle and asked a small group of the photographers and officials to move back, even though they were standing in the rough. He blasted out sideways, across the fairway and into the rough.

From there, he hit a pitch-and-run that threaded the bunkers and raced some 30 feet by the hole. Two putts later, he had a double bogey.

"It was a really, really poor decision on the second shot, and that cost me," Spieth said.

A perfect shot with that 6-iron might have given him a reasonable look at birdie. Anything less and he was asking for trouble, which he got.

"I could have hit a 5-iron easily and just said, 'You know what? I'm out of position. Hit it to 50 feet and two-putt,'" he said. "It just took me three more shots to get to that point."

His troubles didn't end there. He missed the green well to the right on the par-3 16th, so far out of position that he did well just to get it on the green and made bogey. And on the closing hole, he hit a weak fade to the right that failed to clear Barry Burn, the winding, rock-walled creek that meanders along the final two holes.

Spieth wasn't about to blame this on bad breaks, because he got his share of good ones to reach 3 under through 14 holes. His tee shot on No. 1 stopped just short of a pot bunker. His approach on No. 2 hopped off a hillock to about 10 feet for birdie. He made a dangerous play from a pot bunker in the seventh fairway, hitting 9-iron from 137 yards that cleared the top of the lip with inches to spare.

Unlike when he opened with a 78 at the U.S. Open, he said he could at least recover from a 72.

"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," Spieth said, referring to Padraig Harrington and Sergio Garcia finishing at 7-under 277. "So it's not a bad place to be. 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."