Berba is currently in the form of his career at Old Trafford.
On Ferguson, the striker said: "He is probably the most successful manager in football history. At first I was a bit star-struck ... it was just a case of 'whoa'. Then when you start to get to know him he is a very nice guy but when things don't go as he planned, he will give you a rollicking. He can be aggressive, tough. But in a way that motivates you."