Berbatov will return to Old Trafford on Saturday for the first time since his four-year United stay came to an end with a summer switch to Fulham.
Debate still rages amongst the Red Devils faithful about the Bulgarian's merits. But Ferguson said: "I don't think Dimitar was a failure here."
Some point to his hat-trick against Liverpool in September 2010 or the five goals he belted past Blackburn three months later, which helped win the Golden Boot prize along with Carlos Tevez and formed part of an overall tally of 57 goals in 149 appearances, as evidence of genuine class.
Others argue a succession of lacklustre displays - and the fact Ferguson did not even give him a place on the bench for the 2011 Champions League final - is proof of a limited contribution.
In the end, even Ferguson concedes Berbatov was eased out because Javier Hernandez made more of an impact. But he refuses to accept the 31-year-old was a waste of time.
Ferguson added: "Some people like to see players run through brick walls all the time. Dimitar is not that type of player, but he is very talented player and he had a decent goalscoring record here."
The argument goes that Berbatov is better at a club like Fulham, where Martin Jol can construct a team around him, than United, where he was just one of a number of superstars.
Ferguson does not accept the verdict.
"That was not a problem for him," said Ferguson. "The problem for him here was the way we wanted to play and the selections I had to make. When you have choices you hope to make the right one. Javier Hernandez had a fantastic first season with us and as time went on he became a more regular player than Dimitar."
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