Sir Alex Ferguson hopes he never sees another tackle like the one that Emanuel Pogatetz caught Rodrigo Possebon with at Old Trafford on Tuesday night.
Even Middlesbrough manager Gareth Southgate admitted he could have no complaints at the red card instantly shown to Pogatetz during the second half of his side's 3-1 Carling Cup defeat to Manchester United.
"You don't want to see things like that and I hope I never see anything like it again," said the United boss. "It is such a pity for the boy and took the gloss off what was a really good performance."
Possebon needed oxygen on the pitch and was then taken straight to hospital for further treatment, with Ferguson fearing bad news on the 19-year-old Brazilian.
He added: "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 it 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."
Southgate branded the challenge "poor" and admitted members of his bench had stepped out of line.
"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 have no complaints about the decision. 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."
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