TOM WATSON had already won two majors when he locked horns with great rival Jack Nicklaus in golf's Duel in the Sun.

But in spite of his earlier successes in the 1975 Open and the Masters three months earlier, Watson still did not truly believe that he was capable of becoming one of the legends of the game when he arrived at Turnberry in July 1977.

It was only when Nicklaus put his arm around his conqueror at the end of the most engrossing head-to-head in the history of the world's oldest major and told his compatriot that he had given it his best shot that Watson was convinced he was capable of becoming a prolific winner.

"It was a watershed moment because I had trouble winning tournaments," said the 65-year-old on a visit to St Andrews this week.

"Turnberry is the most prominent memory that I have playing the Open Championship and I have many great ones. But that one stands out for several reasons; one being that it was one of the tournaments that I felt I was going to win and I have had only a handful of those in my career, literally.

"It was just a gut feeling. I was playing so well, some of the best golf I have ever played. It just so happened I was playing against Jack Nicklaus.

"It turned out in the last round that I was three shots behind after four holes, got back to even after eight and two shots behind again after 12 before bringing it back to even after 15, where I holed that putt from off the green, which was really lucky, to lead by a shot.

"What was so special was at the 18th Jack caught me by the neck coming off the green and he said, 'Tom, I gave it my best shot and it wasn't good enough. Congratulations. I'm proud of you.'

"That comment coming from the greatest player who has ever played the game was really important to me. It was a watershed moment because I had trouble winning tournaments. Even that year I won four times, but I lost a couple, so they were still calling me a choker.

"It took me a while to learn how to win. But at that point I really had confidence in my game and that I could play with the best players in the world."

Prior to his watershed moment, Watson had struggled psychologically rather than with any technical aspect of his game.

"I think it had become a mental thing," he said. "My confidence always came from my assessment of how I was playing. How are you playing and how are your confidence levels when you're not playing your best?

"Sometimes you are playing in the neighbourhood. Sometimes you're not even close to it.

"Frankly, I have won tournaments when I wasn't even close to the neighbourhood: the US Open in 1982 in the first two rounds.

"But by smoke and mirrors and some fortunate putts I stayed around the lead until Friday.

"Then I went to the practice ground and I found something, and the last two rounds I had a lot more control of my golf swing. But I wasn't remotely close before that and I learned that the light switch can go on."

Watson, who subsequently went on to win a total of eight major champions, has spent the past week in Scotland, mainly at St Andrews where his five Claret Jugs and winner's gold medals will form the centrepiece of a special exhibition mounted in his honour at the expanded British Golf Museum.

Other important artifacts from Watson's career will feature, including the putter he used to beat Australian Jack Newton in a play-off, signed scorecards and rare Championship programmes.

The four-month exhibition, which opens to the public later this month, coincides with Watson's farewell appearance in the Open.

Four of Watson's Open titles were claimed in Scotland: Carnoustie, Turnberry, Muirfield, in 1980, and Royal Troon, two years later.

Victory at the Old Course eluded him with his joint runner-up spot to Seve Ballesteros in 1984 the closest he came to winning at the home of golf.

"As this will be my last walk over the Swilcan Bridge in an Open Championship, I will have so many wonderful Open experiences to remember," he said.

"I am so very grateful for all the years I have been able to compete and the success I have had in the Open.

"But not winning the Open at St Andrews, was that a big disappointment? No, I never really had the disappointment there.

"At the time it was disappointing. I was close, yeah, but it never lasted with me. The only thing that lasted with me when I failed was how did I fail? Why did I fail? What shot did I fail with?

"Then I went to the practice ground and worked on these shots. That's how you deal with failure.

"You learn what you didn't do right and learn for the next time, and that the next time you get in that situation you are successful. That's the way I always looked at failure."

While Watson hopes his game will be in reasonable shape when he bids an emotional farewell at the end of his incredible Open journey, he doubts that he is capable of reproducing the form that left him on the cusp of a record-equalling sixth triumph at Turnberry in 2009 - at the age of 59.

But he remains competitive all the same after revealing: "I am playing next week, in a local championship in Kansas City, called the Watson challenge. It's for players who live in the Kansas City area.

"There will be 48 of us, amateurs and pros. This is our eighth year to find out who is the best player in Kansas City.

"Then I go to the US Senior Open in California, before coming over for the Open Championship and the Senior British Open at Sunningdale."