Sports Desk: Mexico beat South Africa 2-0 in a drama-filled opening match of the World Cup at the Estadio Azteca Thursday, kicking off the biggest ever edition of the global footballing showpiece.Three players were sent off -- two from South Africa and one from Mexico in front of a capacity crowd of 80,000 spectators.South Africa had Sphephelo Sithole dismissed for denying a goalscoring opportunity before Themba Zwane was shown a red card for a slap. Mexico's Cesar Montes was also sent off, for a late foul.Mexico coach Javier Aguirre revealed his players had overcome a serious case of first-day nerves."When you’re starting out the World Cup, of course your legs will shake," Aguirre said. "Never in 25 years had anyone had any cramps but three of them had cramps today.