Juergen Klinsmann said on Sunday he had spent a restless night after he and his Bayern Munich team were booed off following a 3-3 draw at home to Bochum.
Bayern squandered a two-goal lead in the second half and now sit down in 11th place in the table, seven points behind the leaders. Media reports even said some fans were chanting "Klinsmann out!" during Saturday's game.
"That obviously hurts a little," Klinsmann told reporters in Munich. "But the reaction from the fans is understandable given that the results have been unacceptable."
Bayern have won only two of their seven league games so far and the last three matches have produced just one point.
In an interview with the Bayern website Klinsmann said the team owes the supporters a big improvement after the international break.
"We'll identify the errors and individual players will have to accept the criticism," the coach said.
He added: "I feel deep disappointment and even a little anger. We gave away victory in a reckless way.
"I spent a restless night. It hurts but I am a fighter by nature. I know where the problems are."