Claim: John McEnroe was a tennis player.

The Davis Cup is the premier international team event in men 's tennis . It is run by the International Tennis Federation -LRB- ITF -RRB- and is contested annually between teams from competing countries in a knock-out format . It is described by the organisers as the `` World Cup of Tennis '' , and the winners are referred to as the World Champion team . The competition began in 1900 as a challenge between Great Britain and the United States . By 2016 , 135 nations entered teams into the competition . The most successful countries over the history of the tournament are the United States -LRB- winning 32 tournaments and finishing as runners-up 29 times -RRB- and Australia -LRB- winning 28 times , including four occasions with New Zealand as Australasia , and finishing as runners-up 19 times -RRB- . The present champions are Argentina who beat Croatia to win the title for the first time in 2016 .   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 . The Hopman Cup , a third competition for mixed teams , carries less prestige , but is a popular curtain raiser to the tennis season .