Amid all the furore surrounding his move north from West Ham, it was largely overlooked that the Argentina player was placing himself in a far more testing environment that he had ever previously experienced at club level.
Yet, after a slow start, during which time he was asked to shoulder the attacking burden on his own as United tried to cope with Cristiano Ronaldo's suspension and Rooney's latest absence with a broken foot, the former Boca Juniors forward has been outstanding.
"There is a test for every player coming to United," reflected Ferguson. "But with Carlos, there is only one way to answer and that is to look at his form, which has been very good.
"His attitude, both in matches and training, has been excellent and we are very lucky to get him."