MUNICH: Bayern Munich's players are not machines and can also have a bad day, coach Julian Nagelsmann said on Friday in an effort to explain their shock 5-0 demolition at Borussia Moenchengladbach  in the German Cup on Wednesday.

Nagelsmann, who missed the second-round game and will still be in quarantine on Saturday when Bayern visit Union Berlin in the Bundesliga due to his COVID-19 infection, said the heavy loss showed a lot of things went wrong at the same time.

He promised, however, that his team would be completely different against Union.

"We are humans and not machines," Nagelsmann told a virtual news conference on Friday. "We can make mistakes and combined with a good opponent and a bad day for us it led to three goals in (the opening) 21 minutes."

"We showed we are vulnerable but it is important to learn the lessons from this game. It was historic and we have to accept the criticism. No question about that.

"I screamed (watching at home) and the neighbours must have been wondering what was going on. But we are only human and we can make mistakes and sometimes in one day we can make more than one."

The Bavarians suffered their heaviest ever defeat in the German Cup after a dominant start in the Bundesliga and the Champions League where they top their group, having scored 12 goals and conceded none.

In the Bundesliga they have already scored a league record 33 goals in the first nine matches to lead the title race.

"We should not be distracted from too much praise, that we are the best team in the world and all that," Nagelsmann said.

"We have to focus on proving all the time that we are Bayern and that we do indeed belong among the best teams in Europe.

"We need as champions to get up again and we will try on Saturday to show a reaction. We were all a bit surprised about what happened on Wednesday. We agreed that this should not happen again because it is very painful," he said.

Gladbach's three goals in 21 minutes was the first time that Bayern had ever conceded so many in this span in the German Cup.

But 34-year-old Nagelsmann, who is in his first season at the club after spells with Hoffenheim and RB Leipzig, said he did not feel added pressure following the heavy Cup defeat.

"I always feel pressure and here I feel it from day one. In Bayern you have to chase titles and win games. I know how this profession works. I have felt pressure in all the other clubs as well."