With pressure mounting on manager Rafa Benitez after four successive defeats and 2,000 Liverpool fans from the supporters group "Spirit of Shankly" marching to Anfield protesting at the club's ownership by Americans George Gillett and Tom Hicks, Liverpool needed something special against their arch-rivals.
And, perfectly evoking the spirit of their old manager Bill Shankly, Liverpool rose to the occasion to give everyone at the club renewed belief that this could be the season they end their 20-year wait for the title.
The win relieved some of the immediate pressure on Benitez whose gamble to play an "80 percent fit" Fernando Torres paid off with all three points.
Torres, who had missed Liverpool's last two defeats by Sunderland and Olympique Lyon with an adductor muscle injury, scored the opener after 66 minutes and only played because Benitez decided on the way to the stadium to field him.
"I got Fernando's opinion on the coach journey and after talking with the staff decided he would play," Benitez said. "You could see he was not 100 per cent fit, and was not fresh, but sometimes 80 percent of Fernando can make a difference."
Torres told Liverpool's website on Monday that he played through the pain barrier for 80 minutes until he was replaced by David N'Gog who scored the second goal in stoppage time.
"I wasn't really at my best. We knew before the game I couldn't play to 100 per cent because I had some pain in some actions, but in games like this the pain doesn't matter."
"I feel a bit of pain when I shoot across so I could only shoot towards the near post, it was the only thing I could do," he said.
"We are in the race again," Torres added. "We knew before the game that we had to win and we did it. Now we have a bit of confidence but we have to keep it going on Wednesday in the Carling Cup against Arsenal.
"Then we have to be focused for Fulham. But we feel like a strong team again because we're working all together like in the past."
Both teams finished with 10 men after United's Nemanja Vidic was sent off for the third successive match against Liverpool and then hosts' Javier Mascherano was also red-carded by referee Andre Marriner.
