Fabien Barthez believes Paris Saint-Germain did not respect Manchester United in their Champions League clash as the French giants bowed out on Wednesday.
PSG crashed out of the Champions League in the last 16 following a stunning 3-1 second-leg defeat to United in Paris.
Former United goalkeeper Barthez, who won two Premier League titles with the club in 2001 and 2003, criticised PSG afterwards.
"A lack of respect," Barthez told Le Parisien when asked why the French side lost.
"I think these are the first values of an athlete and a team [to respect the opponents].
"It is necessary in all circumstances to respect the adversary. Based on skills, Paris were better. They demonstrated that by winning the first leg against an English team that was even better armed than it was tonight.
"Paris lacked concentration. The players were not in the game. The club that make the difference in this type of meeting are the one that makes no mistake, not necessarily the one who plays the best."
It was PSG's third consecutive last-16 exit in the Champions League, having bowed out in the quarter-finals in the four seasons prior.
Asked if PSG had not learnt their lesson from 2017 when they surrendered a 4-0 first-leg advantage against Barcelona in an incredible 6-1 collapse, Frenchman Barthez – who refused to single out head coach Thomas Tuchel for blame – said: "They have stayed in the same lineage.
"Paris did not learn from their mistake. It is in these moments that we see the history and education of a club.
"They should have won this match on the values. Parisians lacked humility."
He said:"The game we played was unforgivable.
"We have to analyse, think and we have to be men. It's a difficult moment.
"We had to give everything on the pitch. Now it's over, we cannot say 'You had to do that, you had to do this'.
"These are still details, and it's always the case at the high level. I think it's a good time not to talk too much. As we say in Brazil, it's time to eat our own sh*t.
"It's a sh***y moment and we have to keep working."