Worse still, Kahn's private life seems to have hit the rocks again.
Within 48 hours of the game, it was reported that the 34-year-old had split up with his girlfriend, a 22-year-old former barmaid for whom the goalkeeper left his wife a year ago.
The affair, conducted while his wife was pregnant, caused a huge uproar among the German public and Kahn was dubbed a "third-class adulterer".
Now that the relationship seems over and the nightclub barmaid - known as "Lady Verena" in the German media - is heading for a career as a TV celebrity, Kahn is on the back and front pages of the newspapers again.
He says he can separate his private life from football. But yesterday he offered to step down as captain of Bayern. He said: "I have to consider what can be changed and that includes the captaincy. Things cannot continue like this."
This week the respected German football magazine Kicker was asking its readers to take part in a poll on who should be Germany's goalkeeper for next month's European championship finals in Portugal - Kahn, Lehmann or Stuttgart's Timo Hildebrand. But Germany manager Rudi Voeller is refusing to question Kahn's ability in public.
However, the fact remains that three costly mistakes have left Bayern without a trophy this season for the first time for nearly a decade and Kahn's critics have a good case for change.
In the Champions League, Kahn let a long-range free-kick by Roberto Carlos slip through his hands, under his body and into the net as Real Madrid put the Germans out of the competition in the second round.
In the German Cup quarter-finals, another Kahn mistake from a longrange shot allowed Second Division Alemannia Aachen to cause a huge upset. Kahn also let in four first-half goals when Germany were humiliated 5-1 by Romania in a friendly last month.
The Germans could just about stomach England's similar destruction of the national team in Munich three years ago because the English have a higher standing in their eyes.
But Germany's worst away defeat for 65 years was still a huge talking point among football fans in the midst of last weekend's Bundesliga drama.
Kahn is unlikely to be allowed many more blunders.
