Andre Agassi won a tournament.
The 1990 Davis Cup was the 79th edition of the most important tournament between national teams in men 's tennis . The ATP Finals is the second highest tier of men 's tennis tournament after the four Grand Slam tournaments . Andre Agassi . 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 ( Career Grand Slam and Olympic Gold Medal , the other being Rafael Nadal ) , and the only man to win the Career Golden Slam and the ATP Tour World Championships ( won in 1990 ) : a distinction dubbed as a `` Career Super Slam '' by Sports Illustrated . The Grand Slam tournaments , also called majors , are the four most-important annual tennis events .