Roger Federer (born 8 August 1981) is a Swiss professional tennis player. As of January 25, 2010, he has been ranked world number 1 by the Association of Tennis Professionals (ATP), having previously held the number one position for a record 237 consecutive weeks. Many sports analysts, tennis critics, former and current players consider Federer to be the greatest tennis player of all time.

Federer has won 16 Grand Slam singles titles, more than any other male player. He is one of six male players to have captured the career Grand Slam, one of only three (with Laver and Agassi) since the beginning of the Open Era and one of only two male players (the other being Agassi) in history to have won all four Grand Slam titles on three different surfaces (clay, grass and hard courts). Federer has appeared in an unprecedented 22 career Grand Slam finals, and as of January 2010, has reached the semi-finals or better of the last 23 Grand Slam tournaments, a record streak that spans over six years.

John Patrick McEnroe, Jr. (born February 16, 1959) is an American former World No. 1 professional tennis player. McEnroe won seven Grand Slam singles titles—three at Wimbledon and four at the US Open—nine Grand Slam men's doubles titles, and one Grand Slam mixed doubles title. He is remembered for his shot-making artistry and superb volleying; for his famous rivalries with Björn Borg, Jimmy Connors and Ivan Lendl; for his confrontational on-court behavior, which frequently landed him in trouble with umpires and tennis authorities; and for the catchphrase "You can not be serious!" directed toward an umpire during a match at Wimbledon in 1981. He was inducted into the International Tennis Hall of Fame in 1999. McEnroe is also the older brother of Patrick McEnroe, who is also a former professional tennis player and the present Captain of the United States Davis Cup team, a position that John served in previously. They also both are now often commentators for Grand Slam television coverage in the United States.

James Scott "Jimmy" Connors (born September 2, 1952, in East St. Louis, Illinois, also known as "Jimbo") is an American former World No. 1 tennis player and is considered to be one of the greatest tennis players of all time. He held the top ranking for 160 consecutive weeks from July 29, 1974, to August 29, 1977, and an additional eight times during his career (a total of 268 weeks). He won eight Grand Slam singles titles and two Grand Slam doubles titles with Ilie Nastase and was the mixed doubles runner-up with Chris Evert at the 1974 US Open. He is a former coach of Andy Roddick, the winner of the 2003 US Open.

Pete Sampras is a former World No. 1. During his 15-year tour career, he won 14 Grand Slam men's singles titles. This is more titles than any other player except Roger Federer who surpassed this record at Wimbledon in 2009. He had a 204–37 win-loss record over 52 Grand Slam singles tournament appearances. He is regarded as one of the greatest players of all time.

He debuted on the professional tour in 1988 and played his last top-level tournament in 2002 when he won the US Open, defeating longtime rival Andre Agassi in the final. He was the year-end World No. 1 for six consecutive years (1993–1998), a record for the open era and tied for third all-time. His seven Wimbledon singles championships is a record shared with William Renshaw.

Björn Borg (born 6 June 1956) is a former World No. 1 tennis player from Sweden; he won five consecutive Wimbledon titles and is considered to be one of the top players in the history of the sport.

During his relatively brief pro career, Borg won 41 percent of the Grand Slam singles tournaments he entered (11 of 27) and 89.8 percent of the Grand Slam singles matches he played. Both are open era male records for an entire career. In addition, Borg's six French Open singles titles are an all-time record. He is the only player in the open era to win both Wimbledon and the French Open in the same year more than once, winning both for three consecutive years.

Rodney George "Rod" Laver (born 9 August 1938, in Rockhampton, Australia) is a former tennis player from Australia who was the World No. 1 player for seven consecutive years, from 1964 to 1970. He is the only tennis player to have twice won all four Grand Slam singles titles in the same year — first as an amateur in 1962 and second as a professional in 1969. He is the only male player during the open era to have won a calendar year Grand Slam. Laver is rated, along with Roger Federer, Pete Sampras and Björn Borg as one of the greatest male tennis players of all time by many experts and polls. Rod Laver and Roy Emerson are the only male players to win each major title twice in their careers.

Andre Kirk Agassi (born April 29, 1970) is a former World No. 1 professional American tennis player who won eight Grand Slam singles tournaments and an Olympic gold medal in singles. Generally considered by critics and fellow players to be one of the greatest tennis players of all time, he has been called the best service returner in the history of tennis. Known for his unorthodox apparel and attitude, Agassi is often cited as one of the most charismatic players in the history of the game, and is credited for helping revive the popularity of tennis during the 1990s.He is married to fellow retired professional tennis player and multiple Grand Slam champion Steffi Graf.

Ivan Lendl (born March 7, 1960) is a former World No. 1 professional tennis player. Originally from Czechoslovakia, Lendl later became a United States citizen. He was one of the game's most dominant players in the 1980's and remained a top competitor into the early 1990s. Lendl captured eight Grand Slam singles titles. He competed in 19 Grand Slam singles finals, a record for a man since surpassed by Roger Federer in 2009. He reached at least one Grand Slam final for 11 consecutive years, a record for a man since equaled by Pete Sampras.

Boris Franz Becker (born 22 November 1967) is a former World No. 1 professional tennis player from Germany. He is a six-time Grand Slam singles champion, an Olympic gold medalist, and the youngest-ever winner of the men's singles title at Wimbledon at the age of 17. Tennis Magazine put Becker in 18th place on its list of the 40 greatest tennis players from 1965 to 2005. Since he retired from the professional tour, media work and his personal life have kept him in the headlines.

Mats Wilander (born 22 August 1964, in Växjö, Sweden) is a former World No. 1 tennis player from Sweden. From 1982 through 1988, he won seven Grand Slam singles titles (three at the French Open, three at the Australian Open, and one at the US Open), and one Grand Slam men's doubles title (at Wimbledon). He won three of the four Grand Slam singles events in 1988 and finished that year ranked World No. 1. Although he never won the singles title at Wimbledon, Wilander twice won the Australian Open when that tournament was still played on grass courts. This makes Wilander one of only five men (along with Jimmy Connors, Andre Agassi, Rafael Nadal, and Roger Federer) to have won Grand Slam singles titles on grass courts, hardcourts, and clay courts. He is the only man in tennis history to have won at least two Grand Slam singles titles on each of the three surfaces. Wilander won his fourth career Grand Slam singles title at the age of 20, the youngest man in history to have achieved that feat.

Rafael "Rafa" Nadal (born 3 June 1986) is a former World No. 1 Spanish professional tennis player currently ranked No. 4 in the world. Nadal has won six Grand Slam singles titles, the 2008 Olympic gold medal in singles, 15 ATP Masters Series tournaments and also was part of the Spain Davis Cup team that won the finals in 2004 and 2009.

Nadal was ranked World No. 1 from 18 August 2008 to 5 July 2009. Nadal was ranked World No. 2, behind Roger Federer for a record 160 weeks before earning the top spot. In 2009, he became the first player to simultaneously hold Grand Slam titles on clay, grass and hardcourt. His success on clay has earned him the nickname "The King of Clay".