Paris St Germain coach Antoine Kombouare was left frustrated after seeing his team crash to a 3-0 defeat in the Classico against Marseille, calling it "catastrophic".
PSG fans were left fuming by their team's performance against their bitter rivals and attempted to storm the pitch after the third goal before being successfully held back by stewards.
Tension was already high before the match and a fan remains seriously injured in hospital following clashes between PSG fans shortly before kick-off which saw several people arrested.
Riot police, using tear gas, also had to control the crowd during the game, which the Marseille fans had boycotted in protest at the severe security measures that were going to be used to manage them. They will have been disappointed to miss an impressive result against their fierce rivals.
"It's catastrophic," said Kombouare. "We had a really good first half and Marseille were all happy to go in at the break with a 1-0 advantage.
"We were united, solid at the back, all that was missing was some good attacking chances.
"Their second goal came too early in the match, after it became difficult. We came up against a team full of confidence, who scored on each of their attacks.
"On our side, we paid in cash for the slightest error and then had to chase the game. We are also disappointed for our fans. Today we have to remain tight-knit and continue to work in order to lift our heads up again next weekend at Lens."
Before the match Kombouare admitted they needed a victory to get the fans back on their side after a series of disappointing results had seen them slip to 12th in the Ligue 1 standings.
However, the supporters have turned even more against the team and there was added security at the training ground on Monday.
OM in contrast have now emerged as serious title contenders and are three points off league leaders Bordeaux, who have a game in hand. Their players, as promised, have been given two days holiday, but coach Didier Deschamps admits it could have been very different.
"At half-time I told my players that there were miracles in football too," he said. "The miracle would have been even bigger if we had led 2-0.
"We were losing out on the pitch, PSG had a really good first half, they put us under an enormous amount of pressure and aggression. But you can see the difference between a team in confidence, in a positive spiral and a team who are doubting themselves."