From surely impossible, to improbable, to “blow me, it might just happen”, the chances of Tom Watson adding to his five Open victories by winning at the age of 59 are becoming more tantalisingly realistic day by day. He may be tired, but he hasn’t cracked, and his swing remains as sweetly functional as ever.

Watson, who scored a commendable 71 in yesterday’s third round, leads by a stroke from Ross Fisher, an Englishman on the brink of making a major impact, and Mathew Goggin, a journeyman from Tasmania who has never won a tournament on the main US tour. Should he win, Watson will match Harry Vardon’s record of six Opens. He will also become the oldest winner of a major championship in the history of the sport, smashing the record by more than a decade.

Once again, he had a little good fortune, as if he has had the benefit of some “spiritual” assistance, as he put it. After conceding his lead to the younger brigade late in his round, he found fresh inspiration, holing a huge putt on the 16th — as he did on Friday — and taking advantage of a fortuitous bounce on the 17th. He made birdies at both and a par on the last with a typical lack of fuss. “I ended on a real good note again,” he said.

Watson, who had a hip replacement last October and is ranked a lowly 1,373rd in the world, demonstrated his longevity and his mastery of links golf. “I made a game plan,” he said. “I worked how many bogeys I could afford and how many birdies I’d need over the last 36 holes. So far, I’m on course. For some reason, I didn’t feel nervous. I felt serene out there. When I messed up, I didn’t let it bother me.”

The usual scenario on such occasions is for the former champion to summon a few memories of former glories before faltering through fatigue or failing eyesight, gracefully leaving the real business to the younger men. Watson, especially, has suffered from nerves in his later years, mainly when faced with short putts.

But there was little anxiety yesterday. Watson was composed and competitive, and when he was in danger of dropping strokes, he generally found a way to limit the damage. “I scrambled really well today,” he said. “Every now and then the putter works. Boy, it’s working at the right time now.”

Typical was the fifth, the hardest hole. Watson’s long-iron approach trickled into a bunker, where he had a difficult downhill lie. He managed to get the ball out to 10ft from the hole and holed the putt to record his fifth consecutive par. He was fighting hard.

Critically, he putted well and drove the ball beautifully. “I kept the ball in play,” he said. “Drive the ball in the fairway, that’s the most important thing. That’s what Tiger Woods failed to do and that’s why he missed the cut.”

It has been a strange championship, with something of an air of holiday golf about it. As well as a dewy-eyed veteran trying to relive a golden memory from 32 years ago, the upper reaches of the leaderboard have featured a fellow who has never visited Britain before but is just “having a blast”, another who admits to limiting his beer-drinking to four pints a night and one who is ready to depart at a moment’s notice to witness the birth of his first child, whatever the circumstances in the tournament. Meanwhile, the most businesslike competitor of all, Woods, has gone home. The moral seems pretty clear: don’t take it too seriously.

Goggin, whose mother was three times the amateur champion of Australia, plies his trade in the

United States. In his three previous visits to the Open he has not suggested he might be a danger to the principal contenders for the Claret Jug, but his game was not far from immaculate yesterday. His 69 included three birdies and two bogeys. Unshaven and relaxed, he entered into the spirit of things by running more than 150 yards, and at good pace, on to the 16th green and hurriedly marking his ball, as if fearing that it might roll back into the burn. That was never likely, but Goggin hammed the drama up with aplomb.

“It’s been a long time since I ran that far,” he said. “I was tired after I did it, too. It probably wasn’t a very good idea. But when it landed I was a bit shocked and it just looked like it wasn’t going to stay there, so I just had to make sure.”