A stunned Hasan Salihamidzic felt Bayern Munich suffered from a "collective blackout" in their "inexplicable" 5-0 DFB-Pokal thrashing at Borussia Monchengladbach.
The Bundesliga champions suffered a humiliating second-round hammering at Borussia-Park, where they were three goals down after 21 minutes on Wednesday.
Ramy Bensebaini scored twice after Kouadio Kone opened the scoring in the second minute and Breel Embolo rubbed salt into Bayern's wounds with a second-half double.
Bayern were a shambles as they were ripped to pieces by Die Fohlen in the absence of head coach Julian Nagelsmann, who had to watch on at home as he isolates after testing positive for coronavirus.
The Bavarian giants' sporting director Salihamidzic was taken aback by such a woeful performance.
Asked for his reaction to the defeat, he told ARD: "Absolutely shocked. We just weren't there. We didn't win a duel in the first half, it was a collective blackout."
He added: "For me, this is inexplicable. We knew how difficult it would be here, we discussed everything. It is difficult to explain."
1978 - Bayern Munich have lost a game by at least a five-goal margin for the first time since December 1978, 43 years ago, against Fortuna Düsseldorf in Bundesliga (1-7). Stupefaction. #BMGFCB pic.twitter.com/hqaT5D1czf— OptaJean (@OptaJean) October 27, 2021
Dayot Upamecano endured a nightmare outing on his 23rd birthday, looking totally lost and making a poor mistake for the fourth goal from Embolo.
The centre-back was replaced straight after that error, but Salihamidzic says he put a bad night behind him.
"We win together, we lose together. We will rebuild Upa. It's inexplicable because he played really well recently," Salihamidzic said.
Bayern defender Lucas Hernandez also started on a day in which in was revealed he had has avoided jail time for disobeying a restraining order in 2017 after a Madrid court accepted his appeal.
Joshua Kimmich has also been in the headlines recently after stating he had not been vaccinated for COVID-19, but Salihamidzic says off-field issues cannot be used as an excuse.
He said: "[It is] Difficult to say. There were a lot of stories in the past week, but we got along with that in the games before that too. The lack of vaccination was not the reason today that we did not get into the duels and could stop the balls."