FA Cup - Kuyt strikes late as Liverpool beat United
The substitute lashed the ball past David De Gea in the 88th minute to complete a memorable week for Liverpool, three days after they reached the Carling Cup final with an aggregate win over Manchester City.
Daniel Agger headed Liverpool in front on 21 minutes after a De Gea mistake, before Park Ji-Sung restored parity with a crisp finish six minutes before half-time.
Evra was booed throughout due to his involvement in the Luis Suarez case that opened a deep rift between the two clubs.
Suarez, who received an eight-match ban after an independent FA commission found him guilty of racially abusing the Frenchman, watched on from the stands with his family and celebrated the winning goal wildly.
Evra received predictably vociferous jeers whenever he touched the ball, and one fan was pictured making a monkey gesture.
It was unfortunate that he should end up committing a vital error, though he is joined in the United dog house by De Gea who had a miserable afternoon.
He Spaniard is a talented 21-year-old with a bright future, but at present he is a liability on set pieces.
He is indecisive when coming for the ball, a hesitant puncher and too seldom assets himself physically.
Liverpool targeted this weakness, but placing a crowd of players, including Andy Carroll, in front of De Gea on corners.
The move paid dividends when Gerrard delivered from the left on 21 minutes. The goalkeeper, preoccupied with Carroll, found himself caught in no-man's land and Agger planted a firm header into the net - grazing the top of De Gea's head en route.
Thereafter, De Gea was a nervous wreck, spilling simple catches, misplacing passes and appearing terrified by Carroll. Anders Lindegaard can expect to return to the United goal against Stoke on Tuesday.
However, having taken the initiative, Liverpool immediately surrendered it, dropping deeper and deeper in an attempt to cut out United's passing lanes.
However, they broke through when Rafael ran onto an Antonio Valencia flick, beat Jose Enrique and crossed low for Park, who made true contact and sent his first-time shot past Reina into the bottom-right corner.
Both had completed 100 passes by the time the exhausted Scholes went off 15 minutes from time.
But the introduction of Javier Hernandez backfired as Liverpool started to control the midfield battle.
Kuyt failed to get sufficient power on a header from a Jose Enrique cross but the warning signs were there.
Then, two minutes from time, United crumbled in seemingly innocuous circumstances. Carroll got his head to a booming clearance but there should have been no imminent danger.
However, Evra lagged and Kuyt was through on goal - the shot was close to De Gea but had enough power to beat the beleaguered goalkeeper.
The reverberations were felt across the North-West. Is King Kenny really bringing the glory days back to Anfield?