Claim: Andre Agassi was the number 1 tennis player in the world at one point.

Andre Kirk Agassi -LRB- -LSB- ˈɑːndreɪ_ˈæɡəsi -RSB- born April 29 , 1970 -RRB- is an American retired professional tennis player and former World No. 1 who was one of the sport 's most dominant players from the early 1990s to the mid-2000s . Generally considered by critics and fellow players to be one of the greatest tennis players of all time , Agassi has been called the greatest service returner in the history of the game . Described by the BBC upon his retirement as `` perhaps the biggest worldwide star in the sport 's history '' , Agassi compiled performances that , along with his unorthodox apparel and attitude , saw him cited as one of the most charismatic players in the history of the game . As a result , he is credited for helping to revive the popularity of tennis during the 1990s .   In singles tennis , Agassi is an eight-time Grand Slam champion and a 1996 Olympic gold medalist , as well as finishing runner-up in seven other Grand Slam tournaments . During the Open Era , Agassi was the first male player to have won 4 Australian Open titles , a record that was later surpassed by Novak Djokovic when he won his 5th title on 2015 , and then by Roger Federer in 2017 . Agassi is one of five male singles players to achieve the Career Grand Slam in the Open Era and one of eight in history , the first of two to achieve the Career Golden Slam -LRB- Career Grand Slam and Olympic Gold Medal , the other being Rafael Nadal -RRB- , and the only man to win the Career Golden Slam and the ATP Tour World Championships -LRB- won in 1990 -RRB- : a distinction dubbed as a `` Career Super Slam '' by Sports Illustrated .   Agassi was the first male player to win all four Grand Slam tournaments on three different surfaces -LRB- hard , clay and grass -RRB- , and the last American male to win both the French Open -LRB- in 1999 -RRB- and the Australian Open -LRB- in 2003 -RRB- . He also won 17 ATP Masters Series titles and was part of the winning Davis Cup teams in 1990 , 1992 and 1995 . Agassi reached the World No. 1 ranking for the first time in 1995 but was troubled by personal issues during the mid-to-late 1990s and sank to World No. 141 in 1997 , prompting many to believe that his career was over . Agassi returned to World No. 1 in 1999 and enjoyed the most successful run of his career over the next four years . During his 20-plus year tour career , Agassi was known by the nickname `` The Punisher '' .   After suffering from sciatica caused by two bulging discs in his back , a spondylolisthesis -LRB- vertebral displacement -RRB- and a bone spur that interfered with the nerve , Agassi retired from professional tennis on September 3 , 2006 , after losing in the third round of the US Open to Benjamin Becker . He is the founder of the Andre Agassi Charitable Foundation , which has raised over $ 60 million for at-risk children in Southern Nevada . In 2001 , the Foundation opened the Andre Agassi College Preparatory Academy in Las Vegas , a K-12 public charter school for at-risk children . He has been married to fellow tennis player Steffi Graf since 2001 .