Look back to the 1980s and 1990s and a handful of nations were tennis powerhouses. Germany, the US, Sweden and the Czech republic pumped out champions such as Steffi Graf, Pete Sampras, Mats Wilander and Ivan Lendl. Australia, too, was a force to be reckoned with in the men’s game.

These countries still have top stars but the sport’s reach has spread. Now, a Swiss, Spanish, Russian, Argentine or Serb flag is just as likely to flutter by the winner’s trophy. This array of nationalities may be puzzling to those seeking a magic formula to produce tennis champions. Neither size nor weather links the players’ countries. So does money make winners?