Mourinho reportedly took exception with the way City players celebrated the 2-1 win at Old Trafford which that took them 11 points clear of second-place United, the Guardian reported on Monday.
According to the newspaper, players and staff from both clubs had to be separated by police and stewards in the narrow corridor outside the City dressing room.
The row escalated after Mourinho told the victors to turn their music down and to show more respect to the losing side.
Bottles and punches were thrown during and City assistant Mikel Arteta was left with blood streaming down his face from a split eyebrow, according to the Guardian.
The United boss reportedly also became involved in an argument with City's Brazilian goalkeeper Ederson, with the two shouting at each other in Portuguese.
Mourinho then went on to do his post-match media work without mention of the incident, the Guardian said.
According to the newspaper, players and staff from both clubs had to be separated by police and stewards in the narrow corridor outside the City dressing room.
The row escalated after Mourinho told the victors to turn their music down and to show more respect to the losing side.
Bottles and punches were thrown during and City assistant Mikel Arteta was left with blood streaming down his face from a split eyebrow, according to the Guardian.
The United boss reportedly also became involved in an argument with City's Brazilian goalkeeper Ederson, with the two shouting at each other in Portuguese.
Mourinho then went on to do his post-match media work without mention of the incident, the Guardian said.