In two decades of tennis, U.S. player Andre Agassi went from being the young rebel with glam-rock hair to the grand "old man" with a head as smooth as a clay court -- and one of the greatest players in the game's history. He began playing professionally in 1986, and by 1988 had won more than $2 million in prize money. Throughout the 1990s, men's tennis was dominated by the back-and-forth rivalry of Agassi and Pete Sampras
. Agassi's flashy clothes, stylish hair and bad-boy attitude were the perfect counterpoint to Sampras's steady, clean-cut power game. In his career Agassi won more than 850 singles matches, including 60 titles, 8 Grand Slams and an Olympic Gold Medal (Atlanta, 1996). In later years Agassi shaved his head and became a more sober and beloved figure in tennis, still ranking highly after 20 years in the game. In 2005 he made it to the finals of the U.S. Open at age 35 (he lost to Roger Federer
). Plagued by back problems, he retired after losing in the third round the 2006 US Open. He surprised fans by admitting, in his 2009 autobiography, that he had used the drug crystal meth in 1997 and had lied to hide his use from tennis officials.