Anyone who saw the 2002 World Cup final in Japan will remember the image of Oliver Kahn, then often described as the world’s best goalkeeper, remaining between his goalposts long after the final whistle in Yokohama stadium. Filled with shock and despair, his face said it all. The 33-year-old goalkeeper had just made a simple and yet agonizing error in the final against Brazil (0:2). After a shot by Brazil’s Rivaldo in the 67th minute, instead of grabbing the ball Kahn lets it bounce forward, allowing nearby star striker Ronaldo to put Brazil in the lead. There are still 23 minutes to play, but…