Co-caretaker manager Liam Rosenior said bottom-of-the-table Derby County's performance in the 3-0 defeat against Middlesbrough was "unacceptable".
Rosenior, part of a four-strong interim coaching team also including Wayne Rooney, Shay Given and Justin Walker, saw the Rams lose for the second time since they took charge.
The defeat was also Derby's fourth in a row, all of which have seen them fail to score.
"I am not going to stand here and make excuses," Rosenior said. "I just am speechless in what I saw first half in terms of desire, passion, and winning duels.
"I can accept losing when you put a performance in and you put intensity in and energy in the game.