The phrase "living the dream" has been used to mock Leeds United as they tumbled through the divisions, but for the men in white who greeted the final whistle and the 9,000 who had travelled from Yorkshire to witness it, there can be no better description.
It is one of football's great ironies that the club that almost bankrupted itself to compete against Manchester United – and justified their spending with the boast that they had lived the dream – should finally overcome their great rivals in their own temple once they had tumbled into the third tier of English football.
Not even in 1974, when the players marshalled by Don Revie steamrollered their way to the championship and an ageing, ruined Manchester United were relegated, has there been such a chasm between the two clubs. And those who jammed the away end knew it, chanting with rare self-deprecation: "We're not famous any more".
And yet the home-grown men like Richard Naylor and Jonathan Howson, managed by a Yorkshire boy in Simon Grayson, did something achieved by neither the well-drilled teams of Howard Wilkinson nor the sides assembled at ruinous expense under Peter Ridsdale. They came to Old Trafford and won.
Moreover, they deserved to. Sir Alex Ferguson's only quibble about his first defeat at this stage of the FA Cup was the amount of stoppage time. Jermaine Beckford, who in 2004, the year Leeds were relegated from the Premier League, mixed playing for Wealdstone in the Isthmian League with working for the RAC, might have scored three times. Robert Snodgrass's free-kick struck the crossbar and even in the final moments when Casper Ankergren blocked Wayne Rooney's drive, Michael Doyle calmly played the ball out of defence rather than hoofing it upfield. This was not a victory against the grain.
"It has been a fantastic achievement," reflected Grayson, who described the day as on a par with winning promotion with Blackpool at Wembley. "Our club has endured a lot of negativity over the past five or six years with administration and relegation. I said when I first came to the club that it had reached rock bottom and could not go any lower.
"Our fans have deserved this result, not because we have taken 9,000 to Old Trafford; we have taken 4,000 to Bristol Rovers on a Tuesday night. Our fans have backed us when they had excuses not to. They could have downed tools and concluded that football is an expensive business. This is a result for them."
Those supporters would not have wanted to be patronised, to be told they had done well by competing for an hour. However, by 60 minutes they seemed exhausted by their efforts before somehow, and from somewhere, discovering a second wind. With a dozen minutes remaining, Beckford was put clear on goal but directed his shot just wide of Tomasz Kuszczak's post and both he and his manager threw their hands to their heads, contemplating the potential cost of the miss. As if to emphasise it, Snodgrass, who had not been fit enough to start, struck the frame of the United goal but, despite some furious appeals for a penalty when Michael Owen tumbled rather too easily in the box, the kings of the last-minute comeback never seriously threatened.
As the match opened, the Stretford End unfurled a banner featuring a portrait of Eric Cantona and words "Thanks a million", referring to the ludicrously-cheap fee United paid to take the Frenchman across the Pennines. Ferguson referred to Cantona as "the can-opener" for his ability to rip through defences but, an off-key Wayne Rooney apart, he possessed no similar weapons.
Off-key he may have been, but Rooney remained his side's greatest threat. Played through in a rare incisive intervention by Dimitar Berbatov, Rooney advanced on goal but his shot, half-blocked by Ankergren, was shovelled off the line by Jason Crowe.
After almost a decade of Peter Schmeichel, Old Trafford should know all about Danish keepers and, although Grayson remarked that Ankergren was "not exactly peppered with shots", the Dane did everything asked of him, including blocking Danny Welbeck's drive with his knee.
If they were insipid in attack, Manchester United were, to use their manager's own adjective, "shocking" defensively. Apart from one vintage tackle on Doyle, Gary Neville was a shadow of the great player who has graced Old Trafford and took out his frustration with a volley of abuse against the visiting manager. Wes Brown, booked early on, seemed to be doing his best to get himself sent off.
Nemanja Vidic did not even appear, despite being named on the teamsheet, and Ferguson seemed unwilling to dwell on the Serb's explanation that he was not fit enough to play. The majority of the Leeds attacks came down the United left, patrolled by the unfamiliar combination of Welbeck and Fabio da Silva.
The goal came straight down the middle, like a Nicklaus one-iron, propelled by Howson and chased by Beckford and Brown. The man in white got there first and slid his shot from an acute angle between defender and goalkeeper. Kuszczak may have come too early but with more than 70 minutes remaining, United's task did not appear especially daunting.
However, as the minutes drifted by and Ferguson threw on his great talisman Ryan Giggs, a man old enough to recall the pain of 1992 when Leeds overhauled Manchester United to seize the title, an equaliser appeared ever less likely. Yorkshire voices suddenly began singing about Wembley, a venue which in recent years for Leeds has come to be associated with the Johnstone's Paint Trophy rather than the FA Cup.
Manchester United (4-4-2): Kuszczak; Neville, Brown, Evans, F.Da Silva; Obertan (Giggs, 57), Gibson, Anderson (Owen, 69), Welbeck (Valencia, 57); Rooney, Berbatov. Substitutes not used: Amos (gk) Tosic, Carrick, R.Da Silva. Booked: Brown, Gibson.
Leeds United (4-4-2): Ankergren; Crowe, Kisnorbo, Naylor, Hughes (White, 90); Howson (Snodgrass, 77), Doyle, Kilkenny, Johnson; Becchio (Michalik, 88), Beckford. Substitutes not used: Martin (gk), Prutton, Grella, Capaldi.
Referee: Chris Foy (Merseyside).
Booked: Man Utd: Brown, Gibson; Leeds Johnson, Naylor.
Attendance: 74,526. Man of the match: Beckford.
Fourth round Draw details
Leeds' reward for beating Manchester United is a trip to another high-flying Premier League side in Tottenham. Arsenal and Chelsea face tricky away ties at Stoke and Preston respectively and Manchester City visit Scunthorpe. Liverpool will host Burnley should they dispose of Reading in next week's replay, while there are four all-Football League ties. Forest Green, the last remaining non-league outfit, will host Wigan Athletic, if they can first overcome Notts County in their rearranged tie next Tuesday.
Ties to be played 23/24 January
Southampton v Ipswich,
Reading/ Liverpool v Burnley,
Millwall/Derby v Brentford/Doncaster,
Bristol City/ Cardiff v Leicester,
Stoke v Arsenal,
Notts County/Forest Green v Wigan,
Scunthorpe v Man City,
West Brom v Plymouth/Newcastle,
Everton v Nott'm Forest/Birmingham,
Accrington/Gillingham v Fulham,
Bolton v Sheff Utd/QPR,
Portsmouth/ Coventry v Sunderland,
Preston v Chelsea,
Aston Villa v Brighton,
Wolves v Crystal Palace,
Tottenham v Leeds
*Third round Tuesday 12 January
Accrington Stanley v Gillingham
Brentford v Doncaster Rovers
Bristol City v Cardiff City
Notts County v Forest Green Rovers
*Third round replays Tuesday 12 January
Birmingham City v Nottingham Forest
Coventry City v Portsmouth
Derby County v Millwall
QPR v Sheffield United
Wednesday 13 January
Liverpool v Reading
Newcastle United v Plymouth Argyle