World Championship Tennis (WCT) was a tour for professional male tennis players established in 1968 (the first players signed a contract at the end of 1967) and lasted until the emergence of the ATP Tour in 1990. A number of tennis tournaments around the world were affiliated with WCT and players were ranked in a special WCT ranking according to their results in those tournaments.
The WCT had an important impact on the commercial development of tennis. It instituted a tie-breaker system, experimented the "no-ad" scoring system on 40-40 (called at times "sudden death") and outfitted players with colored clothing, a radical idea at that time. WCT also strongly encouraged the audience to cheer for players, rather than politely applaud, as the more staid tennis audiences had done before. They publicly emphasized their prize money structure and special bonus pool as an incentive to attract top players.