With the commencement of the tennis' Open era, the founding of an global professional tennis tour, and incomes from the sales of television rights, the game of tennis has expanded throughout the world and has got rid its English-speaking upper-class representation. Since the 1970s big men's singles and women's singles champions have come out from the former Czechoslovakia (Martina Navratilova, Ivan Lendl and Hana Mandlikova), Germany (Steffi Graf, Boris Becker), Sweden (Stefan Edberg, Björn Borg), Russia (Marat Safin and Yevgeny Kafelnikov), Brazil (Gustavo Kuerten), Belgium (Justine Henin-Hardenne and Kim Clijsters), Switzerland (Roger Federer and Martina Hingis), Spain (Rafael Nadal and Sergi Bruguera), and from other countries.
A lot of great athletes played in the days preceding tennis' Open era, most of whom are unknown by current sports fans. Among the most prominent men's singles players of that time were "Big Bill" Tilden, Fred Perry, Bobby Riggs, Don Budge, Jack Kramer, Frank Sedgman, Pancho Segura, Pancho Gonzales, Lew Hoad, and Ken Rosewall. Any one of these 10 would almost certainly be competitive in modern game of tennis. Other superior men's singles players of the pre-Open era of tennis include "Little Bill" Johnston, Maurice McLoughlin, the "Four Musketeers" (Jacques Brugnon, Jean Borotra, René Lacoste, and Henri Cochet), Vinnie Richards, Vic Seixas, Jack Crawford, and Tony Trabert. Among women's singles the best two pre-Open era players are believed to be Helen Wills Moody and Suzanne Lenglen.
Among the other most prominent men's singles players of the Open era of tennis following may be highlighted: Jimmy Connors, Rod Laver, John Newcombe, Arthur Ashe, Stan Smith, Björn Borg, Ivan Lendl, Mats Wilander, John McEnroe, Stefan Edberg, Thomas Muster, Greg Rusedski, Jim Courier, Goran Ivaniševiæ, Pete Sampras, Michael Chang, Andre Agassi, Lleyton Hewitt, and Andy Roddick. Among the women's singles are Billie Jean King, Margaret Smith Court, Evonne Goolagong, Chris Evert, Monica Seles, Arantxa Sánchez Vicario, Lindsay Davenport, Serena Williams, Venus Williams, Maria Sharapova, and Justine Henin-Hardenne.
Until the early 1950s, Bill Tilden was in general considered the greatest tennis player ever, his only challengers being Budge, Vines, and Kramer. In later 1950s though many believed Pancho Gonzales had taken over that title. Since then on, champions of the tennis's Open era, first Laver, then McEnroe and Borg, followed by Pete Sampras and currently Roger Federer, have been thought the best ever. However, even in the circle of tennis experts, no consent exists.