Gene Sarazen, whose stylish, effective swing and dogged demeanor made him one of the finest golfers of the 1920's and 30's, died yesterday in Naples, Fla. He was 97.

Sarazen died at Naples Community Hospital from complications of pneumonia, said his lawyer, John Cardillo.

His health had been failing in recent years, limiting his access to the game he loved so much. But he returned each spring to Augusta National Golf Club for the Masters, where he served as the honorary tournament starter along with Byron Nelson and Sam Snead every year since 1981, hitting the opening shot of the tournament.

It was at the Masters in 1935 that Sarazen hit the shot that most experts believe is the single most famous stroke of golf ever played. Dubbed ''the shot heard 'round the world,'' Sarazen's shot with a 4-wood at the 15th hole of the last round of the tournament went into the hole from 235 yards away for a double eagle. It helped him earn a tie with Craig Wood, who had finished his round, and Sarazen then won the 36-hole playoff the next day for his only Masters title.

The son of an immigrant Italian carpenter, Sarazen was born Eugene Saraceni in Harrison, N.Y. He began to work as a caddie at the age of 8 and entered his first professional tournament at 17, an unlikely candidate for a career as a golfer. ''In those days, only brokers and bankers played golf,'' he once told The Associated Press.

But he displayed a gift for the game from the beginning. He won the first of his two United States Open championships at the age of 20 in 1922, making him the second-youngest winner in the history of that event, and he was the first of just four men to win all four of golf's major professional championships -- the United States and British Opens, the Masters and the P.G.A. Championship -- during his career. The others were Jack Nicklaus, Ben Hogan and Gary Player. He won 38 tournaments on the PGA Tour, including 7 majors.

An inquisitive and inventive man, Sarazen -- dubbed the Squire of Germantown from his days as a farm owner in Germantown, N.Y., and for his trademark knickers -- was much more than just a golfer. As a young man, he farmed 375 acres of apple orchards in the small community of Germantown, not far from Hyde Park. He was the inventor of the sand wedge, introducing it at the British Open in 1932, and, after he retired from active competition, was a television commentator on ''Shell's Wonderful World of Golf.''

A brilliant shotmaker who could ''do just about anything he wanted to do with a golf ball,'' according to the Masters founder Bob Jones, Sarazen even toured Europe and South America with the trick shot artist Joe Kirkwood. During the 30's, he dominated golf, winning 22 of his 38 PGA Tour titles. But, for all his accomplishments in the game, Sarazen will be remembered best for the single shot that helped turn the Masters from a small, clubby gathering into the enormous event it is today.

In his 1976 book on the Masters, the Atlanta sports columnist Furman Bisher asked Sarazen to describe the shot, and his reply remains the single most vivid recollection of it.

''From the minute I hit the ball there was a feeling in my system that it was going to be close,'' Sarazen recalled. ''The ball went straight for the hole, about 235 yards away. It didn't carry the green. It carried short and rolled about 15 feet to the cup and in. There wasn't that steep incline in front of the green that's there now. If I hit the same shot today, it would roll back in the water.

''The only way I could tell if it dropped or not, those 20 people around the green all jumped up and yelled like hell, and one of them was Bob Jones. He had walked back down from the clubhouse to see (Walter) Hagen and me finish.''

The memory of seeing that stroke hit at the tournament he founded -- then in its second year and known as the Augusta National Invitation Tournament -- was one that Jones always cherished. He referred to it often, and the most eloquent of his recollections was published in the foreword to Sarazen's book.

''I was standing on a mound about 50 yards away,'' Jones wrote. ''His swing into the ball was so perfect and so free, one knew immediately that it was a gorgeous shot. I saw the ball strike the tongue of the green, bound slightly to the left, directly towards the hole, and then the whole gallery began dancing and shouting.''

Those were emotions frequently elicited by Sarazen, who had what Jones called an ''unconcealed and undiminished zest for the game, and for competition.'' Above all else, Sarazen was a competitor. Galleries were drawn to the dapper little man striding swiftly about the course, who stood just 5 feet 5 inches but who played much bigger.

Sarazen had an unquenchable desire to win. That was never more apparent than in 1932 when he came from 9 strokes behind with 28 holes to play to victory, shooting an inward 32 in the third round and following that with a 66 for a three-stroke victory over Phil Perkins and Bobby Cruickshank at Fresh Meadows Country Club in Flushing, N.Y.

His longevity in the game was another hallmark of Sarazen's career. He was 61 when he made his final cut at the Masters, a feat eclipsed only by Snead, who made it at the age of 62. When he was 71 and playing in his last tournament, Sarazen astonished the golfing world by scoring a hole-in-one on the eighth hole during the British Open's first round. In 1996 he was the first recipient of the PGA Tour's lifetime achievement award.

''Good golf is simply a matter of hitting good shots consistently,'' he said. ''And a player can do this for many years after he has passed his physical peak if his swing is fundamentally correct.''

Sarazen lived the last years of his life in Marco Island, Fla. His wife of 62 years, Mary Catherine, died in 1986. He is survived by a daughter, Mary Ann Sarazen, of Marco Island; a son, Gene Sarazen Jr., of Del Ray Beach, Fla.; seven grandchildren, and six great-grandchildren.

Even as he entered his 90's, Sarazen was still able to swing the golf club. At the age of 91, Sarazen swatted his tee shot down the middle of the first fairway at Augusta, a drive that carried more than 150 yards, and finished his swing with a flourish and a wave to the crowd, a huge throng, that cheered his every move.

Later that day, he was sitting in the old manor clubhouse, reflecting on the many things he had seen and done in his career, when the subject of the shot in 1935 was brought up.

''I'm sitting here now and I can remember it almost like it was yesterday,'' Sarazen said, looking out the window down toward the hollow where the 15th hole lay. ''It was quite a thing for me, and for golf, too.''