Slavisa Jokanovic vented his frustration at Fulham after being beaten 1-0 by Birmingham.
The Craven Cottage side conceded a penalty either side of the half-time interval, with Clayton Donaldson converting the second after his first was kept out by David Button.
Austrian defender Michael Madl was sent off a minute before the break, with the scores level, to compound a poor performance from the Whites and condemn them to a first defeat of the season.
He said: "I believe Birmingham played better than we did today. They deserved the points.
"We made so many mistakes during the game, we have some possession of the ball but without getting it to our offensive players. This is my responsibility.
"We have to continue to work hard. We know this kind of situation can happen, with a new team which has been working two and a half months.
"We have to push hard to build a new team with new players and try and improve ourselves. This is our job, we have to continue to go forward."
Part of the Whites' series of errors, saw Madl sent off for two yellow cards, both resulting after sloppy play.
In addition, Donaldson's second half goal came after some woeful Fulham play which saw their defence try to play the ball out from the back under pressure.
And Jokanovic has taken the blame for his men, insisting he pressured them to play that way.
"I want to start playing from the back. My team tried to follow that way, we made many mistakes," he added.
"I want to encourage my players, we have to continue to work on the training ground.
"In a few days we will have another chance. It will be another important game for us, another chance to fight for three points.
"We’re probably going to find a team defending with many players, probably starting with five at the back, and we have to be ready to find a solution."