“I’m assuming that the players know that a first half like the one in Bochum is unacceptable. We were far below our capabilities,” he told reporters on Monday.

The Bundesliga leaders travel to Salzburg on Wednesday for their Champions League last 16 first leg.

“Sometimes it is good that you can play a few days later now in Salzburg and quickly forget such a result,” the former Bayern goalkeeper added.

He recalled that the team had already bounced back well from a heavy German Cup loss to Borussia Mönchengladbach in October.

“We showed the right reaction after the 5-0 defeat to Gladbach and won the next game clearly. And I assume that it will be the same now,” he said.

Kahn does not believe Bayern have a mentality problem, but acknowledged Julian Nagelsmann’s defence needs work.

“When you lose big, people are always too quick to bring up the subject of mentality,” Kahn said. “However, I believe that defensively, not only this season, but in recent seasons, we are missing a few things in our movement and in our work against the ball. We concede too many goals.

“That’s where we have to start. We have to work with more discipline and more passion against the ball. Otherwise, mistakes – and even more so in Europe – will be punished mercilessly.”