Phillip Cocu couldn't hide his anger and disappointment after seeing Derby County beaten 3-0 at Brentford on Saturday.
The Rams were second best throughout and left their supporters dismayed by arguably their poorest performance of the season so far.
And it wasn't lost on Cocu just how disappointing the display was.
He told RamsTV: "If you start any game with the attitude we showed today then maybe it’s better to stay inside because you can’t play at 70/75% in any game, home or away.
“I can accept you don’t have your day, you can play a bad game as a player, it’s football, but I cannot accept what we put on the pitch in the first half.
“If you play 4-3-3, 5-3-2 or 4-4-2, it’s not relevant, because you can see the difference in the second half.
“It’s not a big game from our side. We lost a lot of ball possession but with a much better attitude and it’s an equal game.
“I feel ashamed about our performance in the first half. I told the players that we cannot accept this, not for me, not for the club and especially not for the fans.
“We will need attitude even more now we are in a difficult position in the league. It’s not only about beautiful football, it’s a lot about character in the coming games.
“This will be more important than the football and we cannot show again what we showed in the first half. If you compare it with the aggressiveness of Brentford and how they go deep, how they sprint, how they press, it’s more intense.
“If you are not on this level in this game then it’s hard to play football because all the passes went wrong and we were open.
“It was difficult to turn the game around so I cannot say anymore about the game other than we should be ashamed of our game and also realise my responsibilities. We have had a talk but it will not be the last.”
Cocu, who in interviews elsewhere labelled his players' approach as 'arrogant', says things now have to improve during the international break ahead of the visit of Cardiff City on September 13.
He said: "I’m extremely upset at the moment about my team. I learned something for myself because I am responsible for the team.
“Sometimes it is good to have a break and maybe it’s not bad we have one now. We have some more time for the players who stay and some players will be in a different environment but this cannot happen again.
“We have a few players who will go on international duty but a lot who will stay so with those players, we will look back at the game.
“We are going to show them what we mean so there is no escaping and then we are going to work already.
“We know it’s not all the players who are available but with the players who are, we will work towards the next game against Cardiff.”