Twenty years ago, he was still regarded as the undisputed lord of all he surveyed at Augusta. The legendary Bobby Jones, who created the course, had died in 1971, and over the seasons, Nicklaus had replaced Jones as the Masters' touchstone by bringing his total of victories to a record five.

Yet, synonymous as he was with the event and its sumptuous venue, in 1986 Nicklaus was encountering problems on and off the course. He had fallen to 160th in the PGA Tour money list and hadn't won for the best part of two years, and there was even talk that his business empire was on the brink of collapse.

So, when he arrived at Augusta for the 50th Masters, his financial situation rather than his faltering golf game came under scrutiny.

"My company was a mess, " he later admitted. "Was I in trouble? Sure I was. I could've owed a lot more than I was worth, put it that way."

At 46, with no form as well as a dubious balance sheet, Nicklaus was written off. No one that age had ever won the Masters, and with Seve Ballesteros and Greg Norman in their prime, the tournament would surely become the preserve of the younger players with the confidence and the nerve to survive on Augusta's frighteningly fast greens.

But every prediction was turned on its head, when from a decidedly unpromising position at the start of the final round, Nicklaus stormed through the field to record an extraordinary triumph. In his first cover story for the magazine Sports Illustrated, the American journalist Rick Reilly charted the emotional journey through Amen Corner of "an American legend still under warranty, armed with a putter the size of a hoover attachment".

As many as six shots behind at one stage, Nicklaus bogeyed the 12th and still managed to cover the last 10 holes in an astonishing seven under par. To the accompaniment of a series of deafening roars the like of which had never been heard at Augusta, he dredged up the sort of irresistible charge that had once made him the most feared player in world golf.

There had been Gene Sarazen's historic doubleeagle in 1935, compelling victories by Arnold Palmer in 1960, by Nicklaus himself in 1975, and when Gary Player closed with a 64 to win in 1978, Augusta thought it had seen everything. Later, Larry Mize would stab Norman in the back at the second playoff hole, and Nick Faldo would reopen the wound in 1996, a year before the imperious first coming of Tiger Woods.

Then 2004 saw Phil Mickelson's overdue success at the end of a titanic back-nine struggle with Ernie Els, but memorable as they are, none of those Masters will ever rival the events of 1986.

Nicklaus's sixth green jacket and his 18th major title stands alone because of who won, when he won, and the way he won. After the dust had settled, he turned to his wife Barbara and summed up what had just happened better than all of the millions of words that have since been written about that gleaming, never-to-be-forgotten Sunday afternoon in April. "I finally found that guy I used to know on the golf course, " he said. "It was me."

Nick Price had made the headlines that Saturday with a course record 63 which could have been better had his birdie putt at the 18th not rimmed the hole. "I think Bobby Jones held his hand up from somewhere and said, 'That's enough boy, '" Price suggested. He was now tied for second place with Ballesteros, reigning champion Bernhard Langer and Donnie Hammond, all one shot behind the leader Norman.

Nicklaus, meanwhile, would start the last day four shots in arrears.

On the morning of the final round, one of Nicklaus's sons, Steve, phoned and asked his father more in hope than anything else what would be needed for victory. "Sixty six will tie, and 65 will win, " Nicklaus replied. "Well, go ahead and do it, " said Steve.

If the prediction was to prove eerily correct, by the ninth hole, Nicklaus was doing no better than treading water. Now five shots behind Norman who was in the last group with Price, there were a dozen players ahead of him.

But he birdied both the ninth and the 10th, and in Reilly's words, "Augusta National began to overheat like a $99 Impala".

Nicklaus made it three birdies in a row at the 11th, and suddenly he was only two adrift of the new leader Ballesteros, but then he lost momentum at the demanding 12th hole where a bogey left him three behind. "I don't know why, but that [dropped shot] really got me going, " he said. "I knew I couldn't play defensive with the rest of the course. I knew I needed to be aggressive coming in."

Despite another Nicklaus birdie at the 13th, an ultraconfident Ballesteros eagled the same hole to move four strokes in front. Surveying his second shot into the parfive 15th after a big drive of 298 yards, Nicklaus asked Jackie, his eldest son who was caddying for him, if an eagle might help the cause, before floating a four iron to 12 feet and sinking the putt.

Nicklaus later explained that he couldn't see his fiveiron tee shot in the air at the next hole, the 16th, but he knew he had hit it close. As the ball towered above the flagstick, Jackie was saying, "Be the right club, be the right club, " but even before he could finish, his old man responded: "It is."

Inches from a hole-in-one when the ball pitched, Nicklaus now had to negotiate a tricky three-foot putt for his birdie. "The Bearf has come out of hibernation, " said a youthful Jim Nantz of CBS, who was commentating on his first Masters, as the putt dropped. "All heaven broke loose, " wrote Reilly. Nicklaus was now just one shot behind.

He mightn't have known it, but as Ballesteros contemplated his four iron of 200 yards to the 15th, he was seconds away from the shot that changed his career. "He had an awkward lie and it was a tough situation, " remembered Tom Kite who was playing with the Spaniard.

"The lie, the circumstance, what Nicklaus was doing, the noise. It was so noisy we couldn't even hear each other."

When Ballesteros completed his swing with a onehanded finish, it was obvious the ball was poorly struck and heading towards the water.

Nicklaus was hundreds of yards away at the time, but he may as well have been staring Ballesteros down. He would win another major championship . . . the British Open at Lytham in 1988 . . . but many believed Ballesteros was never the same player again.

"No question, that Masters really hurt my confidence a lot, " he would later admit.

Nicklaus's remarkable charge continued at the 17th where he once again raised his MacGregor Response ZT putter to acclaim yet another birdie and move one shot ahead of Norman and Kite.

MacGregor had been doing little or no business on the putter, but the company sold 350,000 of the oversized model in the weeks that followed.

Overcome by emotion, Nicklaus found himself having to wipe away tears. "I had to say to myself, hey, you've got some golf left to play, " he said. He almost birdied the last, but soaked up the applause for an astonishing 65 and walked towards the clubhouse arm-in-arm with his son. "I was so proud of him, " Jackie explained.

"When he putted out on 18, I told him, 'Dad, I loved seeing you play. It was the thrill of my lifetime.'" If it wasn't the greatest round ever, it was certainly the greatest back nine ever.

Now Nicklaus had to wait because Norman had birdied the 17th and was tied for the lead at nine under par. Norman hit a three wood off the tee and was then caught between a four and a five iron for his second shot. He chose the four, but the shot flared off into the gallery to the right of the green. "I was going for the birdie and the win, " he said, "it was the first time all week I let my ego get the better of me." Norman bogeyed, and Nicklaus had won.

Sam Snead was two shots behind when Nicklaus first won at Augusta in 1963, and now he had straddled a generation to see off both Ballesteros and Norman. As much as Muhammad Ali standing over a stricken Sonny Liston defines a boxing era, the iconic images of Nicklaus, putter aloft in the lengthening afternoon shadows of Augusta 20 years ago, have come to define the Masters.

"Seems like yesterday, " Nicklaus admitted recently.

He's probably not the only one who feels that way.