Ferguson said: “The most valid criticism levelled at us is that we haven’t really signed a replacement for Roy Keane, at least like for like.
“But where is there another Keane? He was a tremendous influence when he wore the red shirt.
“Experience has taught me though that it is not always possible to replace a top man with a clone.
“Roy took over the midfield powerhouse role from Bryan Robson but in many ways they were so different.
“Bryan was one of the best captains I ever had because he could make decisions out on the pitch and could also give you 14 goals a season from midfield.
“Roy had a bigger influence on a game once he had matured, but you have to adapt and not beat your brains out trying to produce a carbon copy.
“For instance, when we failed to get Paul Gascoigne we took Paul Ince instead. Chalk and cheese as players, but Ince became a tremendous servant for this club.
“When Alan Shearer said ‘no’ to us we signed Eric Cantona and in a different way he turned out to more than compensate for missing out on acquiring Shearer.
“So we haven’t found another captain Keane, but we have evolved to produce a midfield every bit as effective as one with Roy in it, with Paul Scholes and Michael Carrick a fantastic pair at the heart of our team.
“Carrick is becoming a major player for us.”
