After 13 holes in the first round of the Open Championship, Jordan Spieth was 3-under par and appeared to be cruising along with the very scoreable par-5 14th on deck.

It all fell apart, though, down the stretch as a disappointing par at No. 14 – which surrendered 76 birdies and 6 eagles on Thursday – was followed by a double bogey on the 15th. The defending champion added two more bogeys on Nos. 16 and 18 to sign for a 1-over 72.

Afterwards, Spieth cited a mental lapse on No. 15 for sending his round into a tailspin, finishing T50 and six shots off the lead.

“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,” said Spieth, who hit 7 of 15 fairways and 10/18 greens.

“It was a really, really poor decision on the second shot, and that cost me.”

Spieth, who’s in the midst of his worst pro season, said that his late collapse on Thursday was a “missed opportunity.”

The 24-year star’s chance at redemption gets underway with a second-round tee time at 9:59 am (EST).

JORDAN SPIETH’S ROUND-ONE STATS

Spieth was less than accurate off the tee and to the greens, but compensated for it with decent putting and scrambling.

TOP-LINE NUMBERS

DRIVING: 297 yards (130th)
FAIRWAYS: 7/15, 46.7% (83rd)
GREENS: 10/18, 55.6% (98th)
PUTTS: 28 (9th)
SCRAMBLING: 5/8 (16th)

ROUND-ONE SCORING

Par 3: +1 (2 Pars, 1 Bogey)
Par 4: E (3 Birdies, 8 Pars, 1 Bogey, 1 Double Bogey)
Par 5: E (2 Pars)
Total: +1 (3 Birdies, 12 Pars, 2 Bogeys, 1 Double Bogey)