Manchester United manager Sir Alex Ferguson accused Manchester City counterpart Roberto Mancini of "badgering" the officials after the pair squared up on the touchline during their teams' clash at the Etihad Stadium.
City prevailed 1-0 thanks to captain Vincent Kompany's first-half header to take them top of the Barclays Premier League table. The managers had to be kept apart by fourth official Mike Jones after a difference of opinion over Nigel de Jong's foul on Danny Welbeck led to angry words and gestures being exchanged.
Ferguson said: "He was badgering the referee the whole game, the fourth official and the linesman, and the minute I go out there... he was complaining about referees all week, he can't be complaining tonight, that's for sure."
Victorious Mancini played the incident down, adding: "I don't remember (what the row was about). I told the fourth official it was a foul for us, not against.
"At that moment the tension was high, but for me it's forgotten."