The Davis Cup is the premier international team event in men's tennis. It is run by the International Tennis Federation (ITF) and is contested annually between teams from competing countries in a knock-out format. The competition began in 1900 as a challenge between Great Britain and the United States. By 2013, 130 nations entered teams into the competition. The most successful countries over the history of the tournament are the United States (winning 32 tournaments and finishing as runners-up 29 times) and Australia (winning 28 times, including four occasions with New Zealand as Australasia, and finishing as runners-up 19 times). The present champion is the Czech Republic, which beat Serbia to retain the title. The women's equivalent of the Davis Cup is the Fed Cup. Australia, the Czech Republic, and the United States are the only countries to have held both Davis Cup and Fed Cup titles in the same year.