Manchester United boss Sir Alex Ferguson says Rio Ferdinand remains untouchable.

Fergie is delighted to have Ferdinand back in contention and insists he remains one of the best defenders in the business, despite concerns about his long-term ­fitness.

He said: "Tomorrow I have Rio back. His experience away from home in matches like these is always ­important.

"There is a slight doubt about Chris Smalling but if Rio is back, then we are ­covered well.

"He's still one of the best. Absolutely. You saw at Bolton, he walked through the game.

"We're absolutely ­delighted with Smalling, (Jonny) Evans and (Phil) Jones.

"The three of them have been ­magnificent and no doubt they're the long-term ­future.

"But there are occasions when you bring in the bit of experience that Rio offers and it does make a difference. Young players know that and particularly young defenders.

"They know there will be times when they're left out for the right ­reasons, knowing they will get better the next time they come in.

"You can't dismiss the kind of experience Rio Ferdinand brings.

"He's missed a couple of games ­after Bolton and he missed one game after West Brom.

"But I don't mind that because having the squad we've got, we utilise it. If he is fit, he will play."