"I was surprised by what has been said, but maybe they (United) are nervous because we are at the top of the table," Benitez said.
"But I want to talk about facts. I want to be clear, I do not want to play mind games too early, although they seem to want to start.
"I have seen some facts. On November 1st, they played Hull and Mr Ferguson had a two-match touchline ban and a £10,000 fine after confronting Mike Dean, the referee, for improper conduct.
"We started the Respect campaign, and that was when Mascherano was sent off last season at Old Trafford. The referee (Steve Bennett) was the referee when they played against Wigan - he could not see the handball against Wigan by Rio Ferdinand, he did not give a penalty. They won the game and they won the title in this game.
"I think it will be the same referee who will be in charge of their game in hand this season (against Wigan). During the Respect campaign - and this is a fact - Mr Ferguson was charged by the FA for improper conduct after comments made about Martin Atkinson and Keith Hackett.
"He was not punished. He is the only manager in the league that cannot be punished for these things.
"Then he was talking about the fixtures. Two years ago we were playing a lot of early kick-offs away on Saturdays when United were playing on Sundays. And we didn't say anything.
"Now he is complaining about everything, that everybody is against United. But the second half of the season will see them playing at home against all the teams at the top of the table, it is a fantastic advantage. But at Christmas, United played on the 29th and the rest of the teams played on the 28th. We were away against Newcastle two days after playing Bolton. They were playing about 40 hours later, they were not complaining then.
"And about his behaviour with referees. The Southampton manager he knows how Mr Ferguson works and how he works, he was very clear. I am not playing mind games, just facts.
"If he wants to talk about fixtures, and have a level playing field as you say in England. There are two options if we don't want more problems with fixtures.
"One is the same as in Spain, the draw for the first part of the league is known, everyone knows which weekend. In the second-half everyone plays the opposite, so you all know.
"Sky and Setanta have the right to choose their games and it will be the same for everyone. So Mr Ferguson will not be complaining about fixtures and a campaign against United.
"Or there is another option. That Mr Ferguson organises the fixtures in his office and sends it to us and everyone will know and cannot complain. That is simple.
"We know what happens every time we go to Old Trafford and the United staff. They are always going man to man with the referees, especially at half-time when they walk close to the referees and they are talking and talking.
"We need to know that I am taking about facts, not my impression. There are things that everyone can see every single week. "Are they under pressure? Maybe they were not thinking that we would be at the top of the table in January. But we are at the top of the table and they are nervous.
"I am not telling the authorities what to do. But I have been here for five years and know how things are going on. I will be watching United's game with Chelsea. The result does not matter to us, if we win at Stoke that result does not matter.
"I was surprised United wanted to start the mind games too early, maybe it is because we are top of the table. But I only wanted to explain our position.
"I have decided that I had a lot of information and I have been watching every single week what has been going on. Then they started talking about us, but every single week we know they will be talking.
"But we want to stay at the top and maybe they will talk about us right to the end. To hear someone talking when he has problems with referees every single week, and now complaining about the fixtures and complaining about everything, I think that is not fair.
"You can see every single week how they put (referees) under pressure, we know this. We have seen it before. We have seen players sent off at Old Trafford and we do not see our opponents sent off. It is part of the game. But to complain and to always have an advantage is not fair.
"We had a meeting in Manchester with managers and FA about the Respect campaign. And I was very clear, forget the campaign because Mr Ferguson was killing the referees, killing Mr Atkinson, killing Mr Hackett. But he is not punished. How can you talk about the respect campaign and criticise the referee every single week?