Roger Federer is a Swiss professional tennis player who is currently ranked world No. 2 by the Association of Tennis Professionals. Many commentators and players regard Federer as the greatest tennis player of all time
What nationality is Ilie Năstase, World No. 1 tennis player in 1973/1974, who won more than 100 ATP professional titles, 7 Grand Slam titles and 4 ATP World Tour Finals championships?
The most successful tennis player to date, with 8 singles titles and 12 doubles titles, in the WTA Tour Championships was originally a citizen of which country?