Then after seeing Watson hit his tee shot close at the par-3 fourth, Spieth holed his bunker shot for a birdie. Watson matched him, and after a Spieth bogey at the fifth, they matched birdies at the par-3 sixth as well. A birdie at the seventh again gave Spieth a two-shot lead.
But the turning point came at the par-5 eighth. Spieth couldn't go for the green in 2, but managed to give himself a birdie chance, then three-putted for bogey. Watson's birdie tied it. And then Watson birdied again at the ninth while Spieth bogeyed.
A four-shot swing in two holes.
Watson bogeyed the 10th but Spieth would never get closer.
On the eve of the tournament, Spieth was the only player in the field who attended the Chairman's Reception at the club.
"He got a chance to spend 30 minutes with Jack," said Spieth's agent, Jay Danzi, who was referring to the Golden Bear. "He soaked it all in."
Apparently Spieth missed the part about hitting the ball over the bunker at the par-3 12th, because he saw his approach land short and roll back into the water. Spieth managed to make a bogey but he would make no birdies the rest of the way.
At the par-5 13th, Watson crushed a 366-yard drive that flew over the trees and into the fairway, setting up a sand wedge approach that left even Spieth gasping.
"I thought it was out of bounds 70 yards left and it's perfect," Spieth said to laughter. "And I guess he knew that when he hit it, too. Ultimately, hats off to him."
Watson became just the third player in the last 22 majors to win multiple major championships, joining Phil Mickelson and Rory McIlroy. He is also the 17th with more than one Masters.
His long-time caddie, Ted Scott, referred to Watson's "Bubba Golf" as a "freak show." Watson, who seemingly can't sit still, squirming and fidgeting all along the way, has never taken a lesson.
"I can't describe it any other way," Scott said. "I've played golf with him probably 40, 50 times and every single day that I play golf with him or watch him play golf I just go, how do you do that? And I asked him on 18, after he hit the tee shot, "Are you from Mars or something? Because I don't believe you can hit these shots that you hit."
Watson led the field in driving distance, averaging 305.63 yards off the tee and was tied for fifth in greens in regulation, hitting 50 of 72 for the week. That's a pretty deadly combination. He was also 16th in putting.
It all added up to a sixth PGA Tour win, a $1.62 million first-place check and another green jacket.
After it was all over, and Watson addressed a gathering on the putting green where defending champion Adam Scott slipped the jacket over his shoulders, tears began to form. They were there again for the televised ceremony, as well as when he met the assembled media.
"Yeah I'm going to cry because why me?" he said. "Why Bubba Watson from Bagad, Florida? Why is he winning? So I just always ask the question why. Why me?
"That's why I'm always going to cry. I'll probably cry again tonight sometime, just thinking about it.
"I got lucky enough to have two green jackets. It's amazing to be up here one time to talk. A second time is amazing."