Referee Mark Clattenburg has hit back at Sir Alex Ferguson's suggestion that Darren Fletcher was shown a "soft" red card during Manchester United's 1-1 draw with Birmingham City on Saturday.
Midfielder Ferguson was given his marching orders in the 84th minute of the St Andrew's clash after being shown two yellow cards.
The Scotland international had been booked for a crunching challenge on Lee Bowyer before clipping the heels of Cameron Jerome after the Blues striker had run past him on the halfway line.
Ferguson could find himself in trouble with the Football Association following his furious touchline reaction to the second booking.
However, Clattenburg is standing by his decision after explaining his motives.
"It's a second yellow card," said Clattenburg. "He was b*****ed for dissent and then he got cautioned for a foul and then he cynically just trips him (Jerome)."
Clattenburg has also explained the confusion over whether to allow United's equaliser, which came via an own goal by Scott Dann.
He continued:"A cross came in from Patrice Evra and the player from the home side scored the own goal.
"What the assistant referee saw was that Wayne Rooney was in an offside position.
"He quite correctly puts his flag up. He asks me whether Wayne Rooney had scored the goal.
"If Rooney had scored, he would have been given offside.
"The law states he must be playing the ball or interfering with play but as Wayne Rooney was two or three yards away, then he wasn't interfering with play.
"He would only have been active, if he had been interfering with the keeper."