It looks like Rooney caught James McCarthy in the side of the head with an elbow although referee Mark Clattenburg did nothing about the incident.
After the game Martinez said: “I saw the incident clearly and the referee did as well because he gave the free-kick.
“Once you give a free-kick it is quite clear that it is a red card. When you look at the replay, it is quite clear he catches James McCarthy in the face with his elbow.”
But Fergie took another view.
He said: “I have had a chance to see it, there is nothing in it.
“But, what will happen, the question has been asked and because it is Wayne Rooney the press will raise a campaign to get him hung by Tuesday or electrocuted or something like that.
“It is unbelievable. Watch the press. It will be interesting to see it.”