Manchester United manager Sir Alex Ferguson accused Manchester City counterpart Roberto Mancini of "badgering" the officials after the pair clashed on the touchline during Monday night's derby 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, above United on goal difference with two games each left to play.
The managers had to be kept apart on the touchline 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, although the pair did shake hands at the final whistle.
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."
TITLE RUN-IN
Manchester City - Pld 36 Pts 83 GD +61
May 6 - Newcastle A (1600 BST)
May 13 - QPR H (1500)
Manchester United - Pld 36 Pts 83 GD +53
May 6 - Swansea H (1330)
May 13 - Sunderland A (1500)