He captained the Bayer Leverkusen side which looked set to make history by winning every competition they entered.
But in the space of a devastating nine days in 2002, Ballack lost the Bundesliga, German Cup final and Champions League final.
A month later Germany went on to lose the World Cup final.
Ballack said: "In four weeks I lost the Bundesliga, the German Cup, the Champions League and the World Cup.
"It was the darkest period of my career. The club had the chance to make history and we won nothing. I thought maybe it could not get worse and then I was suspended for the World Cup final and the team lost to Brazil.
"It was a terrible summer - a memory I don't want to think about. I really hope that will not happen to me and my team-mates at Chelsea."
Ballack has an extra reason ambition to fulfil tomorrow - he has not played at the new Wembley.