The bulk of the 18,809 crowd went home disappointed, a record gate at this stage of the competition.
It's fair to say Leeds have had a tad of luck in several games this term - Leyton Orient springs to mind - but it ran out here as the Shakers became the first side to win at Elland Road this term, with the hosts having held a proud 12-match unbeaten record at home prior to kick-off.
Dennis Wise made six changes from the side which drew in the cup at Hereford with a full debuts handed to Leon Constantine and Filipe Da Costa, a 'second' debut to Mark De Vries while Dubliner Simon Madden made a surprise debut at right-back.
And while the side was shy of first-team regulars, the presence of Tresor Kandol, Jonathon Douglas and Matt Heath on the bench showed that Wise - with a return to Wembley 20 years after he first made his name with the Crazy Gang against Liverpool maybe lurking somewhere in his mind - was treating the much-maligned competition, in its various guises, seriously.
And it certainly proved to be a serious business for all the wrong reasons for Portuguese midfielder Da Costa, who blotted his copybook with a red card three minutes before the interval for a petulant challenge on Wakefield-born Paul Scott.
The dismissal brought down the curtain on an eventful first half which saw Bury grab two goals in the space of five minutes after the hosts were handed the ideal fillip when Constantine fired them in front after just seven minutes.
It looked like being a long evening for the Shakers when Leeds drew first blood when Seb Carole's lofted pass with the outside of his boot caught out Ben Futcher, and was latched onto by Constantine, who displayed all the predatory nous that saw him bag 26 goals for Port Vale last term.
He certainly showed how to make friends and influence people by showing pace, power and no little coolness in steering the ball past Provett after proving too hot to handle for Futcher - the prelude to a few embryonic cries of "Wembley, Wembley".
Little was seen of the visitors as an attacking force in the early stages as they looked every inch a side schooled in the mould of ex-Lincoln boss and Bury director of football Keith Alexander, namely preferring perspiration to inspiration with a fair few hoofs to boot.
De Vries then tested the reflexes of Provett, who turned away his precision effort and all looked set fair. But a crazy spell then turned the game on its head with the Shakers - unbeaten in 11 games prior to last week's loss at Rotherham - restoring parity on 24 minutes.
A booming delivery from Brian Barry-Murphy was sent goalwards by the head of 6ft 7in Bradfordian Futcher - who once notched 11 goals in a season for Lincoln - with his effort crossing the line despite the best efforts of skipper-for-the-night David Prutton, with Lucas rooted to the spot.
Jonny Howson then fired a screamer just over into the Kop before Bury again stretched Leeds' wobbling rearguard.
The impressive Nicky Adams saw his effort tipped over by Lucas after good work by Bishop as play switched to the other end and from another corner, Bury - with the bit between their teeth - took the lead to cap a frenetic spell when rabbits-in-headlights defending enabled Bishop - in the running for the FA Cup player-of-the-round following his 10-minute hat-trick against Workington on Saturday - to crown a dream few days.
He coolly picked his spot following defensive consternation with his steered effort beating Lucas.
Howson and Carole were then off the beam as the hosts sought an instant riposte before United copped a major blow when Da Costa received his marching orders for violent conduct, to leave them with it all to do.
Douglas came on for Prutton at the interval with Dave Bassett assuming touchline duties with first-team coach John Gannon.
After a slow opening, opportunities arrived at regular intervals, with De Vries seeing an effort deflected wide before spurning a golden chance just past the hour mark when he latched onto Lucas' punt and outmuscled Futcher before wastefully dragging his shot wide of a gaping goal.
And the former Hearts man had his head in his hands soon after when he fired off target following Carole's floated corner.
Kandol was then thrown into the fray to form a striking triumvirate with De Vries and Constantine and it was the latter who was left to curse after his point-blank header was brilliantly parried by Provett.
Kandol then powered another heaven-sent chance off target following Madden's fine cross before the Irishman almost made it a debut to savour when his downward header brought out another spellbinding reaction save from Provett after he supplemented the attack.
Incredibly, more was to come with the keeper superbly turning away a stinging low shot from Paul Huntington as the pressure kept on at apace.
At the other end, the workaholic Adams spurned a great chance to seal it with his close-range effort blocked by Lucas ahead of home pressure which saw them throw everything but the kitchen sink at Bury, with Heath, thrown up front for a tiring De Vries, seeing a header blocked.
Somehow Bury survived.