Kuyt knocks United out at Anfield
The match, somewhat unusually, contained very few flashpoints until Andy Carroll's flick-on put Kuyt through to fire the clincher in the 88th minute. Prior to that it appeared the tie was heading towards a replay neither manager really wanted, after Park Ji-Sung had cancelled out Daniel Agger's header in the first half.
"It's been a fantastic week for the players. Everyone realises the history of the football club and the players want to be part of it," said Liverpool manager Kenny Dalglish, whose side reached the League Cup final on Wednesday.
"It was a magnificent effort from them. After the game on Wednesday, to come back on Saturday morning and win showed tremendous commitment and great heart. United might have been the better side and had more possession but other than them hitting the woodwork once, Pepe [Reina] didn't have that much to do."
United manager Sir Alex Ferguson was adamant his side had not deserved to lose. "I don't know how we lost it," he said. "But I think in the context of an FA Cup game it can happen. One bad breakaway and you can lose a game. It was a bad goal because we didn't deserve to be beaten. We were the better team. But that's FA Cup football. It can happen."
De Gea struggles
On his last visit to Anfield, David de Gea 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 Carroll out of his way allowed Agger to rise highest to head home Steven Gerrard's cross.
Just moments earlier United had almost taken the lead when Antonio Valencia cut in from the right to fire a shot past Pepe Reina which rebounded back off his right-hand post. Jamie Carragher, on his 34th birthday, was brought into the starting line-up, but an unfamiliar holding role in front of the back four for the veteran handed the midfield initiative to the visitors.
Following the opening goal, United enjoyed a long spell of possession, knocking the ball around in midfield without any end product. But just when they looked like squandering their dominance they equalised, as Rafael da Silva 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 into the bottom right corner.
Early in the second half Ryan Giggs' cross from the left to the far post resulted in a moment of panic for Agger, but the Denmark international cleared with his knee under pressure from Valencia.
Smalling had a similar episode of concern as he slipped when dealing with Enrique's pass into the penalty area, with Carroll's appeal for handball after he smashed the ball at the centre-back falling on deaf ears.
As the game started to open up, 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.
The Carragher experiment was brought to an end in the 63rd minute when he was replaced by Kuyt, while Charlie Adam came on for Rodriguez. De Gea's difficult afternoon continued as he allowed a Stewart Downing cross to slip through his fingers for a corner, although he managed to hold on from a Gerrard free-kick.
Kuyt claims the winner
With 18 minutes remaining Craig Bellamy, the midweek hero against Manchester City in the League Cup, surprisingly replaced Gerrard, before Adam sent a long-range strike wide and Kuyt put a weak header from Downing's cross off target.
The Netherlands international made up for his miss two minutes from time, though, when he popped up with the winner. Reina's punt downfield was flicked on by Carroll and Kuyt got ahead of Patrice Evra to fire past De Gea.
It was only his second goal of the season, his other coming in the League Cup, but was as vital as the hat-trick he scored on this ground in the victory over against United last season. Kuyt could have put the result beyond doubt moments later when Carroll crashed a header against the angle of post and crossbar, but the forward put the rebound wide.
The visitors looked for a way back in the closing stages but there was not enough time to respond. Liverpool duly extended their unbeaten run at home to United to five matches, making up for some of the hurt felt after their third-round exit at Old Trafford a year ago, in what was manager Dalglish's first match back in his second spell in charge.