History
The Hopman Cup competition is an unusual international tennis team event in two respects: It involves male and female players, and the players are invited, not selected by their national governing bodies.
Although the first competition didn't begin until December of 1988, the Hopman Cup grew out of discussions about a mixed team championship among Australian tennis players in 1984. One of those players, Paul McNamee, began actively pursuing the idea after he retired from competitive tennis in 1988.
The West Australian Lawn Tennis Association agreed to sanction the event and the Burswood International Resort Casino of Perth agreed to host it. McNamee also received the support of Lucy Hopman, widow of Harry Hopman, the coach who guided Australia to 15 Davis Cup titles from 1938 through 1969. She agreed to allow the competition to use her late husband's name.
The format established by McNamee and the WALTA was simple: Each participating country would be represented by a male player and female player and the outcome of two singles matches and one doubles match would determine the winner in contests between two countries.
Currently, eight countries take part. They're divided into two groups of four each for a preliminary round robin. The top two teams in each group then meet in a playoff and the playoff winners meet for the championship.