Mancini insists teams are scared of playing Manchester United.
But Fergie hit back at the Manchester City boss and said: "That's absolute nonsense. The English game is the most honest in the world. I think we all recognise that.
"There's no way any team could come to Old Trafford and not do their best. That also applies to the Etihad, Stamford Bridge, the Emirates or Anfield.
"They all do their best because that's the nature of the English game. So it's absolute nonsense what he said. He was maybe looking for a bit of self-sympathy or something like that."