Mauricio Pochettino was not afraid to voice his frustration after Paris Saint-Germain's 3-0 loss at Monaco on Sunday lunchtime.
Wissam Ben Yedder scored the first and third goals, with Kevin Volland netting the second, in what was a humiliating display for the current Ligue 1 leaders.
"It's unacceptable to start a game like that. After that, it was a disgrace in sporting terms," Pochettino said afterwards.
"Now it's time to move on, get over the frustration of the Champions League and think about giving our best while having a competitive attitude.
"I don't want to look for excuses.
"The first half was unacceptable. We had no fighting spirit. The way we played is not acceptable. This can't happen.
"We can't have this kind of attitude. It is unacceptable to start the game in this way. Respect for the club and our fans is fundamental. The important thing is to find solutions.
"Behaviour must be more collective than individual. We have moved away from that. We have to think collectively."
PSG have a 13-point lead over Rennes at the top of the Ligue 1 table.