After three days of thrust and counter-thrust, Augusta saved most of its final round drama for just two holes.
Having found four birdies in his first seven, 20-year-old Spieth stood on the tee at the eighth two shots clear, and perhaps just starting to believe that it could all start with the crowning glory.
Then, in the blink of an eye, two bogeys met two Watson birdies, and the 2012 champion had opened up a lead which he would not relinquish.
And in the end, for the man who famously has never had a golf lesson, this seemed almost quite routine.
No sign here of a Jean Van de Velde-style meltdown, or of a Phil Mickelson-like surge from the pack. Spieth’s round tailed off with six consecutive pars to finish, and he spoke afterwards of “mixed emotions”.
For a man of his age, though, to complete 72 holes at Augusta on debut without worse than a bogey is little short of a miracle, and he will be a Major champion before too long.
Blixt finished alongside Spieth on five under, having completed his fourth under par round of the week with a third successive 71.
The Swede has made a great virtue of consistency – his July 2013 triumph in the Greenbrier Classic featured a 66 and a trio of 67s – and he now boasts a record of two top four finishes in only three major appearances.
He, too, will surely continue to feature at the higher echelons of the Majors for some time to come.
Miguel Angel Jimenez claimed fourth place after following up his third round 66 with a solid 71.
He heads now for the Senior Champions Tour, but as Fred Couples (who carded a 75 to finish in a tie for 20th place here) and Tom Watson have shown recently, this may not be the end of his hopes of contending.
Bernhard Langer, another multiple Masters winner now prominent on the senior circuit, finished tied for eighth after a 69, his lowest round of the week.
The potential British challenge, meanwhile, hardly materialised. Justin Rose and Lee Westwood flickered, faded and never truly featured, finishing at one over and one under respectively.
Rory McIlroy shot a 69 to finish tied for eighth at level par, his best Masters finish. His tournament, though, was once more ruined by one wayward round – this is his fifth consecutive Masters to feature a 77 or worse.
If he can rid himself of the tendency for self-destruction and harness his stellar talent for all four days here, he will don a Green Jacket one day.
Sunday, and this year, though, was all about Watson, who was one of only five men to break 70 on the final day as the 13 players who had begun Sunday under par were whittled down to just seven by the end.
He would later admit to telling his caddie coming up the 18th that he “didn’t remember the last few holes” and that he was “just hanging on”, but hang on he most certainly did.
He said afterwards that he plays golf “because I love it. I love the game. I want to grow the game”.
While there may be finer technicians on the tour, players with scientifically crafted swings and metronomic putting strokes, when it comes to growing the game, to stand at the vanguard there can surely be none better than Bubba.
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