Jack Fleck had the slimmest of resumes as a professional tournament golfer. He had never come close to winning on the PGA Tour, and was in the mere qualifier category when it came time for the 1955 U.S. Open at the Olympic Golf Club in San Francisco. A qualifier, in the parlance, is not even a contender; he just fills out the field. Yet Fleck got himself into a playoff with Ben Hogan, one of the greatest players in golf history, for the game's most prestigious title. And when Fleck defeated Hogan, it was not just surprising, it was incredible. How could a nondescript journeyman pro defeat a golfer who was revered as the ultimate champion golfer? Especially after Hogan had won it four times already? This book presents a thrilling play-by-play, shot-by-shot recounting that brings back to life the look and feel of the entire three days of regular play and, most tellingly, the fourth-day playoff itself. Relying on first-hand sources, The Upset reveals the players' mental processes as they strategized their game and handled their emotions. And it finally offers a convincing explanation for Fleck's mind-boggling victory, which was considered at the time and remains to this day one of the most unexpected outcomes in all sports history.