But the young Texan produced a stunning birdie-eagle-birdie-birdie response to restore his lead that thrust him towards glory. Well, it relates to the picture above, where Spieth holidayed in Cabo alongside Michael Jordan and Michael Phelps - the two greatest in their respective sports.
But what no one could have known in that moment was that the putt on 13, the one that kept him away from a double and kept him within a shot of Kuchar, was the beginning of the most remarkable four-hole stretch in the history of major championship golf, four holes that felt like the back nine Jack Nicklaus played at Augusta in 1986, when the 46-year-old Nicklaus shot 30 coming home and almost shot 29 and won the last of his 18 major championships.
"All of a sudden, I now have a 1-shot lead after that hole in the British Open with five to go", Kuchar said. He sliced it horribly out of the tee box. After a long delay, Spieth finally took an unplayable and dropped into a bind shot.
"We took our time getting the line, getting the number", Spieth's caddie said of the odd situation that took 21 minutes to unfold.
His blind three iron cleared the dune and ended up in front of a bunker short of the green.
There's a tie at the top midway through the final round of the British Open. Spieth in particular struggled, falling to three over after the first four holes before striking a spectator with a wild drive at the sixth.
"When that (birdie) putt went in was my first vocal appreciation of the day". He scrambled for bogey at No. 13 an trailed Kuchar by one heading to the par-4 14th.
The next closest to challenging was China's Li Haotong, who had five birdies in nine holes from the eighth to get to four under.
Spieth, Koepka and Kuchar were tied for the lead entering the second round.More news: Mourinho Reveals How Long He Wants To Be At Man Utd
"Is Jordan Spieth something else?"
Grace put it to within 2 feet for his final putt.
While I was still mulling over what happened with my two rounds, one had to stand up and appreciate what Branden Grace was doing at Birkdale.
Spieth, meanwhile, was stumbling early.
At one stage McIlroy had closed to within four shots of the lead and birdied the ninth and 11th holes with an eagle on the 17th.
Emotions rolling, Spieth followed with a 30-foot birdie at the 16th and was ahead by two. The one exception was the 2016 Masters, where he frittered away a five-stroke advantage on the final nine holes and lost by three.
Realistically, Kuchar is the only person that could challenge Spieth.
Spieth didn't make a bogey all day in the third round as he shot a 65. Jordan Spieth will win more majors. Spieth hit his tee shot into the left rough, while Kuchar split the fairway. Instead they were at the back of the 18th green when Kuchar saw them for the first time, "a teary surprise" as he called it. He finished with a bogey on the hole.
In near ideal conditions, the South African journeyman made five birdies against no bogeys to move to even par in the tournament. Cameron was crying. After a roller-coaster back nine when he held it all together in the most trying of circumstances, daddy's emotions also showed. We know he has the Masters scoring record but this flourish even had Johnny Miller, not quick to praise, calling it the greatest finish he'd ever seen. Now he has won the first three legs of a Grand Slam before the age of 24 the way Nicklaus did.
Kuchar was the only player within five shots of Spieth.