United won 3-1, but boss Sir Alex Ferguson was more concerned for the welfare of Possebon and launched a scathing attack on Austrian Pogatetz: "The injury looked really bad and the lad has gone to hospital.
"The thing that gets me about challenges like that is that the opponent always claims he has done nothing wrong.
"He (Pogatetz) should have just walked off the field. Then you get their bench screaming that is wasn't a sending-off and there is nothing wrong with our player.
"At least Gareth Southgate was very good about it. He apologised and understood the gravity. It was an absolutely terrible tackle."
Gareth Southgate admitted Pogatetz had left the referee little option than to dismiss him, although the Boro boss insisted his captain had worked hard to clean up a previously dismal disciplinary record.
"We can have no complaints about the decision," admitted the former England star.
"It is difficult to know why it happened. It was an unusual aberration for him because his discipline has improved in the last two years."
Southgate also confirmed he had tried to placate Ferguson, who had reacted so furiously to the comments from Boro's bench.
"A couple of lads on our bench did not have the same view as I did but that is dealt with now," he said.
"We can only hope the lad recovers."
Southgate is likely to take disciplinary action against Pogatetz, who will be suspended from Boro's next three matches, although Possebon's absence is likely to be far longer.