Benitez said: "In 20 years nobody could say these things but maybe a lot of people are thinking the same as me. I do not regret saying it.
"I can guarantee a lot of people have sent a lot of messages, not to me but to our staff and a lot of people in Liverpool. It is one person saying what everyone wants to say.
"But I was not thinking about what people think, I was thinking about my club and Mr Ferguson's comments on Liverpool this season. You can understand why."
Asked if he thought Ferguson was nervous, Benitez responded: "Clearly", before adding: "Maybe he is a little bit scared."
United face Chelsea on Sunday and a draw would suit Benitez, who will watch the match from the comfort of his armchair.
"I cannot change the game so I will stay at home, watch it on television and enjoy," he said.
"It is clear both cannot win. We will see what happens. A draw could be a perfect result.
"I know him (Ferguson) for five years now and people are saying he is playing mind games. I think it is too early.
"He is talking too much about Liverpool. He has to think about his own team, the problems they have and all the things they are doing."