Rafael Benitez defended Javier Mascherano after his run-in with referee Steve Bennett left Liverpool with 10 men and proved decisive in their 3-0 defeat to Manchester United.

The Liverpool boss had seen the influential Argentinian midfielder given a second yellow card in a turbulent first half at Old Trafford.

And the Spaniard admitted he was trying to tell Mascherano to "finish" his row with the official after he was shown the card which ultimately left Liverpool with 10 men for the second half.

"The player knows he has made a mistake, but in this kind of game to be sent off just for 'asking', I find it a difficult decision to understand," Benitez said.

"I don't know whether it was anything to do with the Ashley Cole incident, you will have to ask the referee.

"Javier was sent off for dissent, but to be sent off for asking the official something is a surprise. He knows he made a mistake, but in a big game like this it is difficult to understand.

"I was talking with him in Spanish, he told me he was just asking, but I was saying 'finish' because you cannot change things.

"Javier is a fantastic professional and has been playing for years at the maximum level. He just did not understand.

"I was trying to say to him 'finish, finish' - but we are still very disappointed with the decision."

Benitez continued: "When you are a professional and play a big game like this, you are surprised at such a sending-off and you want to know why. It was a surprise for everyone.

"Was the referee intimidated by the crowd? I don't know, you must ask him.

"If you want to win you must have passion in a big game, and sometimes you make mistakes, but he was only asking the referee about a bad tackle.

"I have talked to him and he knows it was a mistake. But he was booked earlier for a tackle and did not understand why. I felt the sending-off was difficult to understand.

"I do not think that just to 'ask' is a big problem in the end. Maybe Javier does not know the referees."

Manchester United boss Sir Alex Ferguson was delighted with the victory on an important weekend in the title race.

Ferguson felt the decision to send off Mascherano had cost Liverpool but his side were deserved winners.

"I know they had 10 men in the second half, but we played some very good football throughout, particularly in the first period with our attention, to pass and move," he said.

"We could have been three up in the first half, with a couple of one-v-ones, and then we were deservedly in front.

"Then came the sending-off. The boy had already been booked and dissent is dissent, I feel he should not have got involved.

"He had run from centre midfield to get involved with the referee. And with things that happened in the week with the Ashley Cole incident, there is now a focus on dissent."

Wes Brown scored his first goal for three years to set United on the road to their emphatic victory. Cristiano Ronaldo and Nani completed the scoring late in the second period.

Ferguson added: "It was a brave header from Brown for the first one, he doesn't get many but that was excellent. In the end we controlled the match and we were the better team, that is the real key.

"We started to get the breaks, Ronaldo could have had a hat-trick, Wayne Rooney could also have had a hat-trick, they both had one-on-one chances with the goalkeeper.

"In the end we should have finished them off earlier. On the day, once we had the second goal that was it. I feel that 3-0 was not a flattering score, we could have got more.

"It was good to play like that and beat our biggest rivals, we did our job and have three more points and a good goal difference."

So, Rafa backs him and says you can always question the ref.  I can see where he's coming from, but I have to say what would it be like if there were a steward's enquiry into every refereeing decision? Surely the default position should be that the ref is right, and only if it is exceptional should you ask the ref-and then it should prolly be the captain who asks. Maybe that type of ruling would help.  Though it won't, given how much they are paid.  Start fining them 3 months salary for a yellow card-that'll sort it out right away.