'I was on the bus when it hit me' - the day Leeds United stunned Manchester United at Old Trafford
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The two sides, though, came to blows in the FA Cup third round in 2010, which is the last time the pair met across the Pennines before Sunday afternoon's top flight meeting.
The Red Devils were champions of England while the Elland Road club had fallen on hard times amid their financial crash which saw them begin a Football League nightmare that would last until last summer.
In January 2010, the Whites made what used to be a very familiar journey with the odds stacked against them in the famous competition.
Simon Grayson's League One leaders were backed by an army of supporters, as 9,000 Whites fans made the trip across the M62 more in hope than expectation.
Leeds entered the game unbeaten in 15 games, but were given still given little chance of pulling off the unimaginable against the then 11-time winners.
Sir Alex Ferguson had never seen his Manchester United side exit the FA Cup at the third round stage, nor had his Red Devils outfit ever been knocked out of the Cup by a lower division team.
United began the afternoon as underdogs, but by the time referee Chris Foy was blowing the full-time whistle, those who were in attendance were rubbing their eyes in disbelief.
Celebrations went on long into the evening, with fans locked inside the ground afterwards.
Whites' terrace favourite Jermaine Beckford struck in the 19th minute as he latched onto a long ball from Morley-born midfielder Jonny Howson before slotting home past onrushing goalkeeper Tomasz Kuszczak.
The Stretford End was left stunned, Leeds fans were sent into delirium before 71 breathless minutes followed. Grayson's side battled and they battled hard.
Casper Ankergren made saves, Jason Crowe cleared off the line, Beckford and Howson squared up to Wes Brown as Paddy Kisnorbo bled for the cause. Robert Snodgrass even hit the bar.
Beckford's goal has now been immortalised in the Elland Road club's history, with barely a matchday passing by without his name and exploits at Old Trafford being sung about.
For one man in particular, that day unfolded in front of his very eyes and feet, and Howson, the Thorp Arch academy product, will never forget the day his beloved Whites knocked their bitter rivals out of English football's most famous competition.
"It was a great feeling," Howson told the Yorkshire Evening Post last year.
"I remember being sat on the bus outside the stadium afterwards while we were waiting for the other lads and I must admit I just couldn't believe we'd actually done it.
"That was probably when it actually all sank in. It was another great moment and a memory that will live with me for the rest of my life.
"It's a fair few years ago now but to me it only feels like two minutes."
Howson also achieved promotion with the club that same season before departing for pastures new in 2012, while the Red Devils ended the season without a trophy.
But on reflection, the midfielder says the dramatic day against Bristol Rovers in LS11 and hauling Leeds back into the Championship in front of a packed Elland Road, just beats that famous day nearly 11 years ago.
"I'd say the promotion," Howson smiled.
"Just because it actually achieved something. Don't get me wrong, obviously beating Manchester United in the FA Cup was a tremendous achievement - but actually getting a promotion and in the manner that we did was incredible.
"I was sat on the bench and Max [Gradel] gets sent off. We went down to 10 men and they scored just after half-time. I must admit you're sat there on the bench and when you can't affect it, you're thinking it could be the play-offs again.
"Obviously, when you get the call, you just try to make a difference and give it a lift. Luckily, I managed to do that and Jermaine [Beckford] did what he does best by putting the ball in the back of the net and gets us the win."