The romance built over four intoxicating days in Ayrshire.
But thousands of hearts around the world were broken when he finally capitulated in a play-off to Stewart Cink.
Having won five Opens and three Senior British Opens, including the 2003 tournament at Turnberry, the adoring British crowd had roared on Watson from the moment he carded an opening 65.
Instead of making way for the young guns after enjoying his moment in the limelight as the usual script demands of men his age, Watson refused to retreat.
Back in a share of the lead after day two, the whispers started. "He couldn't, could he?" Still in front after day three, Watson became the favourite to add the final chapter to a remarkable story.
The pen was primed, too, but the final stroke let him down as he hit a poor putt on the 18th for the title.
For many, the dream faded there and then. And it died completely when Watson blew up over the final two extra holes. He suddenly looked a man his age, and A Duel in the Evening Sun it was not.
"It's a great disappointment. It tears at your gut," said Watson.
"But I take from this week just a lot of warmth, a lot of spirituality, in the sense that there was something out there. It helped me along."
Cink delighted with first major title
The focus on Watson is to take nothing away from Cink, who holed out from 15ft on the 18th to set Watson a target and then held his nerve to make his own dream come true and claim a first major title.
"I had mixed feelings out there because I watched him with admiration all week," said Cink.
The Open Championship can always be relied on to provide compelling stories and drama of the highest order.
Last year, Tiger Woods was absent with injury but he wasn't missed as Greg Norman and Padraig Harrington took centre stage.
At Turnberry, Watson and Ross Fisher, praying that his wife could delay the birth of their first child, were the threads of the last two days which lacked nothing in excitement and intrigue despite Woods having this time missed the cut.
The world number one may be on his way to being the greatest golfer ever, but the Open is bigger.
Running in parallel with the will-she, won't-she of Mrs Fisher's impending delivery was the seemingly perennial question of when was a Briton going to win the Open again.
Fisher and Lee Westwood were best placed in the second-last group to become the first Briton since Paul Lawrie in 1999 and the first Englishman to win the Open since Nick Faldo in 1992.
As the final day unfolded and Fisher fell away, 21-year-old Chris Wood almost beat them to it, finishing tied third with Westwood while countryman Luke Donald also ended in the top five.
Earlier in the week, we wondered if Harrington could make it three Open titles in a row.
Harrington finished this year's Championship on a total of 12 over
The struggling champion did at least make the cut, but his reign had to end sometime, and with the pressure lifted he may be able to resurrect his game to the heights of last year. The Lyle v Monty spat also provided a spiky sidebar.
But it was Watson's tale. There's unlikely to be a sequel - Watson is set to play his last Open at St Andrews next year before he becomes too old - but then who would have thought 32 years ago he would have a putt to win a second Open Championship at Turnberry?
As the massed media filed sombrely into Watson's news conference, the old competitor, who has tasted many victories and defeats over the years, joked: "This ain't a funeral, you know."
Deeply disappointed but philosophical, he was asked to provide his own headline.
"The old fogey almost did it," he chuckled. "It would have been a hell of a story."
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