Plymouth manager John Sheridan was heavily critical of his side after their 1-0 loss at Burton.
Callum McFadzean's goal left Plymouth, who have now taken only one point from three games, looking like outsiders for a place in the play-offs.
The visitors came to life after the break but Reuben Reid's shot was deflected the wrong side of the post and Conor Hourihane could only shoot into the arms of goalkeeper Rob Lainton.
He said: "I've told the players how I feel because I'm very disapponted with the way we played.
"We're trying to get in a position we're we can challenge for something, but I thought the difference between the teams was Burton played like a team that wants automatic promotion.
"We played like a side who are happy just to stay in the league. I very rarely have a go at my players, but a performance like that is unacceptable.
"I usually just have a few words about how the game has gone, but we can't come and perform like that.
"We just did not get going, we didn't disturb them in the middle of the pitch, and the goal just about summed up the performance.
"We just thrown away a great opportunity to improve our position - just as we have done in the last two games."