Dirk Kuyt hit the late winner as Liverpool gained revenge for their FA Cup exit at the hands of Manchester United a year ago with a 2-1 victory.
Park Ji-sung's equaliser just before half-time had looked like sending the tie to a replay after Daniel Agger's header had put the hosts ahead. However, Kuyt, with only his second goal of the season, fired past David de Gea late on.
Off-field matters had dominated pre-match proceedings as both sides tried to ease tensions ahead of the first meeting of the two sides since Luis Suarez's eight-match ban for racially abusing Patrice Evra. But while there was plenty of animosity in the ground between rival fans, the match itself contained very few flashpoints.
The United captain took it all in his stride, particularly in a strong challenge from Stewart Downing, but the temperament of goalkeeper De Gea was more open to question.
On his last visit to Anfield the Spaniard had produced an impressive display to earn United a 1-1 draw, but after one early save from Maxi Rodriguez he began to look slightly more shaky on his first appearance in 2012. De Gea would have been relieved to see Jose Enrique's long-range strike deflect behind off Chris Smalling.
But he exposed himself to criticism at the resulting corner as his preoccupation with trying to push Andy Carroll out of his way allowed Agger to rise highest to head home Steven Gerrard's cross. Just moments earlier Antonio Valencia had cut in from the right to fire a shot past Jose Reina which rebounded back off his right-hand post.
Following the opening goal United enjoyed a long spell of possession, knocking the ball around in midfield without any end product. Rafael da Silva then shrugged off Enrique far too easily to get to the byline and drill over a low cross from the right which Park smashed first time past Reina and into the bottom right corner.
As the game started to open up in the second half, Michael Carrick's defence-splitting pass saw Danny Welbeck knock the ball past Reina but Martin Skrtel got back to clear as the shot trickled goalwards. De Gea then allowed a Downing cross to slip through his fingers for a corner, although he managed to hold on from a Gerrard free-kick.
With 18 minutes remaining Craig Bellamy surprisingly replaced Gerrard, before Charlie Adam sent a long-range strike wide and Kuyt put a weak header from Downing's cross off target.
But he made up for his miss two minutes from time when he popped up with the winner. Reina's punt downfield was flicked on by Carroll and Kuyt got ahead of Evra to fire past De Gea. Kuyt could have put the result beyond doubt moments later when Carroll crashed a header against the angle of post and crossbar but the striker stabbed the rebound wide.