Heated exchanges took place involving Jose Mourinho and some of City's players, it is understood, with the United boss reportedly involved in a confrontation with City goalkeeper Ederson.
Jose Mourinho has been unable to provide assurances Eric Bailly will play again this season as he provided a worrying injury update on the Manchester United defender.
The United boss then had a carton of milk thrown towards him from inside the dressing room which hit one of his backroom staff, according to Sky sources, while Manchester City assistant coach Mikel Arteta suffered a cut to the head in the incident but no punches were thrown.
Asked about Sunday's incident, Mourinho indicated he was unhappy with City's behaviour, adding that his team had showed more respect to Arsenal following their recent 3-1 win at The Emirates. No respect for Eddie Howe. "If it is over now, then I will go on holiday to Brazil or Los Angeles", he said, However, he refused to look beyond Sunday's encounter at West Bromwich Albion. You don't respect them?
When asked if there was a hangover after losing to Pep Guardiola's men, Mourinho said: "Fatigue, yes, but hangover - no". But I also know that he really likes me as a person, so there's no issue about the discipline being for the wrong reasons.
"We know that 11 points is a big gap but I can think back to when Sir Alex Ferguson was manager and the gap was something like nine points and we ended up losing the title. We have to enjoy those moments". Bournemouth can be a risky side but they aren't playing well enough to get anything tonight so I'm backing United to bounce back with a routine win. "We won a derby", he said of a Premier League-record 14th consecutive win.
"It was to celebrate inside the locker room".