Tennis is a racket sport that can be played individually against a single opponent (singles) or between two teams of two players each (doubles). Each player uses a tennis racket that is strung with cord to strike a hollow rubber ball covered with felt over or around a net and into the opponent’s court. The object of the game is to manoeuvre the ball in such a way that the opponent is not able to play a valid return. The player who is unable to return the ball validly will not gain a point, while the opposite player will.[1][2]

Tennis is an Olympic sport and is played at all levels of society and at all ages. The sport can be played by anyone who can hold a racket, including wheelchair users. The modern game of tennis originated in BirminghamEngland, in the late 19th century as lawn tennis.[3] It had close connections both to various field (lawn) games such as croquet and bowls as well as to the older racket sport today called real tennis.[4]

The rules of modern tennis have changed little since the 1890s. Two exceptions are that until 1961 the server had to keep one foot on the ground at all times,[5][6] and the adoption of the tiebreak in the 1970s.[7] A recent addition to professional tennis has been the adoption of electronic review technology coupled with a point-challenge system, which allows a player to contest the line call of a point, a system known as Hawk-Eye.[8][9]

Tennis is played by millions of recreational players and is also a popular worldwide spectator sport.[10] The four Grand Slam tournaments (also referred to as the Majors) are especially popular: the Australian Open played on hard courts, the French Open played on red clay courtsWimbledon played on grass courts, and the US Open also played on hard courts.[11]