Jermaine Beckford's first-half goal secured a memorable 1-0 victory for Leeds United at Old Trafford here on Sunday and ended two of Sir Alex Ferguson's proud Manchester United FA Cup records.
The veteran manager had never lost in the third round and never been knocked out by a team from a lower division in 22 seasons of FA Cup football but the League One leaders, 43 places below their hosts, ensured both records disappeared along with United's interest in the tournament for another season.
Defeat also meant United had lost in the third round of the FA Cup for the first time since being beaten by Bournemouth in 1984, AFP reported.
The intense rivalry between Manchester United and Leeds ensured this was an out of the ordinary tie even before the dramatic events unfolded.
The 9,000 travelling fans who had made the journey over from West Yorkshire generated an atmosphere all too often lacking at Old Trafford and those supporters did not have long to wait to have something to cheer.
Leeds's goal came in the 19th minute and was created by a magnificent 50-yard pass from Jonathan Howson who, having won the ball halfway inside his own half down the right, found Beckford.
The prolific forward appeared to have miscontrolled the ball for a moment but managed to make a decisive touch and roll the ball beyond Wes Brown and the dive of goalkeeper Tomasz Kuszczak.
Old Trafford was stunned, apart from the delirious corner of the ground housing the visiting supporters, and the sense of disbelief continued two minutes later when Howson's cross from the right-hand by-line found the unmarked Luciano Becchio who should have done better than head over.
Ferguson had promised a strong team and few changes from the line-up that blew aside Wigan 5-0 in the Premier league in midweek but, eventually, opted for seven changes and a relatively inexperienced side. Ferguson 'shocked' by Man Utd Cup exit
It looked a dangerous gamble and, thankfully for the United manager, he still had Wayne Rooney on the field for the in-form England forward looked his team?s best, if not only, route back into the tie.
In the 24th minute, Rooney was sent scurrying down the right and he appeared to have successfully lobbed keeper Casper Ankergren only for full-back Jason Crowe to recover and make a magnificent goal-line clearance.
There was also a growing air of malevolence on the field and a booking for Brown, for a foul on Becchio.
Then came a touchline confrontation between Gary Neville and Leeds manager Simon Grayson, over whether United should return possession to Leeds from a throw-in following an injury, added fuel to the fire.
There was more of the same after the restart - United appealing for a penalty after a Howson challenge on Danny Welbeck and a melee between both sets of players after a collision between Brown and Michael Doyle.
But there was also some pulsating football being played with Ankergren required to save from Welbeck and Dimitar Berbatov in quick succession although Ferguson, before the hour was up, brought on Ryan Giggs and Antonio Valencia in an attempt to rescue the situation.
Michael Owen would soon also follow them into the fray as the situation became ever more dire for the Premier League champions.
A pair of chances fell to Rooney, either of which should have brought an equaliser, but in the 70th minute he shot over after Owen had completely miskicked eight yards out then, six minutes later, fired wastefully over from Valencia's pull back.
Yet the opportunities were starting to come Leeds' way, also.
Beckford really should have put the tie beyond all doubt in the 77th minute when he sent a low drive whistling beyond Kuszczak's right-hand post.
More unlucky was Leeds substitute Robert Snodgrass whose 80th minute, 20-yard free-kick struck the crossbar and flew to safety.
In a frantic finale, Owen glanced a header just wide and Ankergren saved superbly from Rooney with Fabio missing the ricochet but the third tier side were ultimately full value for their upset.