The 42-year-old was also one of the game's greatest ambassadors. A flamboyant character, his distinctive plus-four trousers always marked him out from the crowd.

The triple-Major winner was enjoying the best spell of his career for some time and was ranked eighth in the world.

Stewart won his first Major at the 1989 USPGA Championships and then secured the US Open in 1991.

He had one of the smoothest swings in the sport which led observers at the time to wonder why he had not achieved more in his career than those two major wins.

Already taking medication for an enlarged heart and suffering from a degenerative disc in the lower back, the answer came in 1995 when he was diagnosed as suffering from Attention Deficit Disorder.

Stewart's 1999 US Open victory capped a tough comeback for the 42-year-old

His inability to fully concentrate during the crucial final holes of tournaments was finally understood.

But he worked hard with psychologists to overcome the disorder and resurrected his career.

He was runner-up at the 1998 US Open and then capped his comeback with victory in one of the most thrilling US Opens of all time just four months ago.

He holed a 15-foot putt on the final green, the longest winning putt in the history of the competition, to beat fellow American Phil Mickelson.

A devout Christian, he thanked God for bringing him the second Open title of his colourful career.

"If it weren't for him, I wouldn't have had the faith to win again," he said at the time.

His faith saw him through the heartbreak of watching his father die a lingering death from cancer in 1996. His mother is a recovering alcoholic.

Stewart (left) lost his Ryder Cup singles match to Colin Montgomerie

His belief did not prevent him from being one of the most intensely competitive golfers on the American tour.

A veteran of five Ryder Cups, he was one of the American team who did most to spark the tension in the build up to last month's competition in Boston.

"On paper, these European guys shouldn't even be caddying for us," he said a few days before the event.

Yet despite his desire to win he was the embodiment of sportsmanship.

He lost his 1999 Ryder Cup singles match to Colin Montgomerie - but could have salvaged a half had he not conceded the final putt to his opponent in the most noble of gestures.

He was the most outspoken American critic of the excesses of this year's event - in particular the treatment of Montgomerie at the hands of US hecklers.

Although he won the US Open twice, it was his lifelong ambition to win the Open Championship in Britain.

Unfulfilled dream

Ben Crenshaw, his close friend and captain of this year's Ryder Cup team, said: "He particularly loved playing in the British Isles.

"He desperately wanted to win the Open Championship and figured in a few but he enjoyed his off-times over there too.

"Golf (in Britain) has an added dimension that we do not have in America. He loved that, the challenge - and the weather.

"All of us golfers have lost a great friend. We like to think of ourselves as one big family."

Stewart was always his own man. He once teed off at a tournament wearing garb made entirely America's star-spangled flag.

Colourful attire

His colourful gear dates back to 1982 when, playing in Asia, he saw two other competitors wearing plus-fours.

"They kept telling me on windy days you don't have anything flapping around your shoes while you're standing over a putt."

So he ordered a pair and wore them ever since - but only for competitive rounds.

Fervently patriotic, he cried when they played the national anthem at his first Ryder Cup.

Yet behind that immaculate image was one of the most straightforward and direct players in the game.

Jose Maria Olazabal, who as Masters champion was due to play Stewart in the Grand Slam of Golf featuring all four of this season's major winners in Hawaii next month, said:

"He was a true sportsman on the course and a gentleman off it. He never failed to conduct himself in the true manner.