MANCHESTER, England (AFP) - Manchester United manager Sir Alex Ferguson branded Emanuel Pogatetz's challenge on Rodrigo Possebon "horrendous" after the young Brazilian was left with a suspected broken leg on his debut for the English and European champions.

Possebon was stretchered off after 65 minutes of United's 3-1 victory against Middlesbrough in the third round of the League Cup at Old Trafford following a studs-up challenge which earned the visiting captain a straight red card.

The challenge drew a furious response from Ferguson who remonstrated on the touchline with Middlesbrough coach Colin Cooper and had a heated debate with manager Gareth Southgate.

Ferguson was clearly still sickened by the incident after a comfortable victory which featured goals from the returning Cristiano Ronaldo, Ryan Giggs and Nani, cancelling out an equaliser from Adam Johnson.

Ferguson said: "The boy is off to hospital and it looked a really bad one. For the kid to make his first team debut and get an injury like that, it was pretty horrendous to be honest with you.

"For ten minutes after it, everyone was numb and we lost our momentum but the thing about those challenges is it is always the case that the opponent claims he is innocent.

"That's what I couldn't understand. He should have walked right off. One of their bench was screaming that he shouldn't have been sent off and that there was nothing wrong with our player.

"At least Gareth Southgate apologised, he understood the gravity of it and was very, very apologetic but it was a terrible tackle. I've seen the video of it and I really don't want to see it again."

Southgate made no excuses for his captain's savage assault on the United man and explained how he had calmed the situation with the United manager.

"He won the ball but he caught him with his following foot," said Southgate. "I have no complaints about the sending off and just have to hope that if he is seriously hurt the lad gets a full and speedy recovery.

"Obviously, in the context of the game, it turned the game against us as well, but our first thoughts are with the lad.

"A couple of lads on our bench didn't have the same view of it that I did. I could see it was a bad one and I think we have dealt with that with Sir Alex now. I explained that to him and put it right."

Pogatetz has been known to relish the physical side of the game and, although his manager made no attempt to defend the foul which left a large and gaping gash on Possebon's right shin, he refused to reveal what punishment he will hand out.

"That's not something I want to talk about publically," said Southgate. "I have no complaints about the sending off, we apologised to the player and everything else stays within the club.

"I have to say the last two years he has worked incredibly hard on his disciplinary record. That was an unusual aberration for him in that period of time.

"He has taken the responsibility of captain very well and, if you speak to referees this season, they will say he has been a credit the way he has captained the team. It is difficult to know why what has happened tonight but there is nothing you can do about that."

The evening should have been a comfortable and successful one for United given that Ronaldo started a game for the first time this season, scoring and completing an hour of impressive action.

"We have plenty of big games coming up so that was important," added Ferguson. "We have players who need the games.

"Cristiano, as he has done many times before, climbed above the defenders, his spring is terrific and Ryan's finish was absolutely fabulous. I was pleased with a good performance, it's just a pity about the boy's injury and I just hope there is nothing serious. But it looks bad."