Sir Alex Ferguson believes his Manchester United side did not get a fair crack of the whip from referee Andre Marriner at Anfield.
Nemanja Vidic was sent off for two yellow cards and Ferguson questioned a number of the official's decisions as they slumped to their first defeat in 12 games in all competitions as Liverpool triumphed 2-0.
Goals from Fernando Torres and David Ngog ended Liverpool's run of four successive losses and eased the pressure on manager Rafael Benitez.
While Ferguson thought Liverpool deserved to win, he claimed that Marriner was swayed by the home crowd.
He felt Vidic was unlucky to be red-carded, that home defender Jamie Carragher should have been dismissed and Michael Carrick was denied a penalty.
Ferguson said: "It is very difficult atmosphere here. There was a wounded animal aspect to the game and it was something we did not overcome.
"I think it affected our players and it affected the referee. There were so many controversial things that happened we have to feel aggrieved at some of them.
"The Vidic booking was the worst decision. It is a foul, fine. But the player has played on, he won the second ball and knocked it for a throw in and got booked. It put Nemanja under pressure.
"The most controversial decision was Carragher bringing down Michael Owen. He was clear through.
"The laws of the game were altered to prevent professional fouls of that nature and if Carragher goes off, he is their best player and their captain. It would have been a different game. They would have been under pressure.
"The referee was only four or five yards from it and he cannot use a covering defender as an excuse. Michael was clean through. With Michael's pace he is going to get away from him."
Ferguson was also incensed United were not awarded a spot-kick for a Carragher challenge on Michael Carrick.
"He has gone right over the top of the ball, " said the United boss. "If it is outside of the box it is a free-kick and maybe a yellow card.
"But it was inside the box and the referee was only six yards from it. It was another bad decision."
Ferguson did, however, conceded Liverpool were worthy winners.
"Liverpool were the better team and I am not taking anything away from them at all," he said.
"They deserved to win the game as it was a disappointing performance from us. We were not good enough."
Torres opened the scoring in the 65th minute with his ninth goal of the season and Ngog sealed the victory in stoppage time.
United remain two points adrift of Chelsea at the top of the table and Ferguson insists they will recover.
He added: "Part of the challenge is to get over disappointments. Last season we lost at home 4-1 to Liverpool which was a travesty but we went on to win the league."
