Tiger Woods
The World No.1 returned to golf two months after a serious knee injury, and, although in considerable pain, won the US Open, his 14th major championship and his most remarkable victory to date.  Woods had surgery on his left knee in April, but decided he had recovered sufficiently to play in the US Open at Torrey Pines in June. It proved to be one of the most exciting major championships ever as Woods, wincing with pain after many of his shots, birdied the final hole to force a play-off with Rocco Mediate, which he won. 
Two days after his unlikely victory, Woods announced that he would need reconstructive surgery on his knee and withdrew from the rest of the season.  As one of his rivals Kenny Perry said afterwards: “He beat everybody on one leg.”