Sir Alex Ferguson marked the 23rd anniversary of his appointment as Manchester United manager yesterday by observing that age is no barrier, so long as one retains the hunger to succeed. He might just as easily have been talking about the Chelsea team who lie in wait for United tomorrow, having gone a long way towards disproving his assessment of them as a team that had passed their peak.

Ferguson said of Chelsea before the start of last season that “I don’t see outstanding progress coming from a team in their thirties”, adding “I just don’t know how far that team has got to go.”

He has consistently claimed that his comments were misinterpreted, but, with Chelsea top of the Barclays Premier League and likely to field a starting line-up tomorrow with an average of just over 30 years, Ferguson conceded that, under the management of Carlo Ancelotti, their age and experience have proved to be a virtue.

“I think Chelsea are using their experience really well,” Ferguson said. “Frank Lampard has retained that fantastic energy to get down the pitch and you would have to say that his record in terms of appearances is quite exceptional for a midfield player. He’s 31, but he obviously looks after himself to get that kind of playing record. They’ve got an exceptional player there and very, very good experience in the rest of the team. Experience can be important.

“Carlo Ancelotti was a great coach at AC Milan and he has brought a wealth of experience with him to Chelsea. He’s won the European Cup twice and he was also a great player, so he has that wealth of knowledge. I thought he’d do well. He has brought a different system to the one Chelsea used and it seems to be working well. When you have those kinds of players, it’s easier for them to adapt than younger ones because they have more tactical knowledge.”

Chelsea lead United by two points in the Premier League, having won nine of their first 11 matches, and recorded what they regard as another significant victory yesterday when they received the all clear to strengthen their squad when the January transfer window opens.

Fifa, world football’s governing body, had imposed a 12-month transfer embargo on Chelsea after finding them guilty of “inducing” Gaël Kakuta, the French youngster, to break his contract with Lens and move to London in 2007, but sanctions against the club have been suspended while the Court of Arbitration for Sport investigates the case.

Ferguson did not know yesterday morning that the reprieve, temporary or otherwise, was on its way for Chelsea. He had earlier suggested that the African Cup of Nations in January — which is likely to mean their squad being deprived of John Obi Mikel, Michael Essien, Salomon Kalou and Didier Drogba for up to a month — will pose a challenge for Chelsea.

“I hope so,” Ferguson said when asked if the tournament might disrupt Chelsea’s season. “We all think that way when we’re talking about our opponents and what can happen to them. The African Nations Cup is a difficult thing. You can lose players for up to a month. But a lot depends on the programme they’ve got. Chelsea have a pretty big squad. We shouldn’t be looking at January. We should be concentrating on Sunday.”

The long-term concern for United at present is the condition of Rio Ferdinand, with Ferguson hinting yesterday that surgery may be the only option as the club’s medical staff attempt to resolve a persistent calf injury that they suspect might be related to the England defender’s longstanding back problem.

“We don’t know exactly where the calf injury is coming from, whether it is coming from the lower back or whether it’s a nerve thing,” Ferguson said. “Calf injuries are usually two to three weeks, but there’s no sign of him recovering from this injury. We’re looking at the whole situation, but in the meantime he’s out. There’s no improvement, put it that way, so we’re looking at something different.”

Nemanja Vidic is fit to return to the United team, however, and is likely to partner Jonny Evans in the centre of defence.