While traditional sets continue until a player wins at least six games by a margin of at least two games there are some alternative set scoring formats in use. A common alternative set format is the eight or nine game pro set. Instead of playing until one player reaches six games with a margin of two games, one plays until one player wins eight or nine games with a margin of two games. A tie-break is then played at eight or nine games all. While the format is not used in modern professional matches or recognized by the ITF rules, it was supposedly used in early professional tours. It is commonly utilized in various amateur leagues and high school tennis as a shorter alternative to a best of three match, but longer than a traditional tie-break set. In addition, eight game pro sets were used during doubles for all Division I college dual matches, until the 2014–2015 season.
The player who would normally be serving after 6–6 is the one to serve first in the tiebreak, and the tiebreak is considered a service game for this player. The server begins his or her service from the deuce court and serves one point. After the first point, the serve changes to the first server's opponent. Each player then serves two consecutive points for the remainder of the tiebreak. The first of each two-point sequence starts from the server's advantage court and the second starts from the deuce court. In this way, the sum of the scores is even when the server serves from the deuce court. After every six points, the players switch ends of the court; note that the side-changes during the tiebreak will occur in the middle of a server's two-point sequence. At the end of the tiebreak, the players switch ends of the court again, since the set score is always odd (13 games).
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 Birmingham, England, in the late 19th century as lawn tennis. 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. During most of the 19th century, in fact, the term tennis referred to real tennis, not lawn tennis.