A superb late finish from Joe Riley saw Bury end Sheffield United's resistance at Bramall Lane this afternoon.
The 85th minute goal, which left Mark Howard grasping at thin air, effectively settled a match which, for long periods, had threatened to boil over thanks in no small part to the erratic decision-making of the officials.
United, who until Tom Pope broke the deadlock had actually looked the more likely to score, levelled when Billy Sharp converted from the penalty spot.
But Riley's intervention proved decisive as Nigel Adkins' side slipped to its second defeat of the League One season with Leon Clarke twisting the knife during added time.
Chris Basham, the United midfielder, had urged his team mates to start on the front foot and they obliged although clear cut chances proved elusive. Conor Sammon was inches away from connecting with a Kieran Freeman cross moments during the early skirmishes which also saw both Tom Soares and Martyn Woolford booked for clumsy challenges.
With United launching quick balls forward - one from David Edgar, despite failing to reach its intended target, earned a round of applause from ADKINS - Sammon continued to pose a threat. Midway through the opening period, Rob Lainton parried a header from the Irishman away following Jamal Campbell-Ryce's centre before a burrowing run nearly prised Bury's rearguard apart.
Louis Reed, with Jose Baxter serving the final game of a three match suspension, was again selected in midfield and, after sweeping a free-kick just past Lainton's left hand upright, sent a scuttling shot wide after combining with Sammon.
Soares was fortunate to escape a second caution moments before the break as tempers began to boil just below the surface. Again, United seized the initiative when the second-half got underway. Bury, looking to rid the contest of any rhythm, also continued in the same vein with substitute Reece Brown clattering into Campbell-Ryce after Clarke had gone down under a seemingly routine challenge.
In between, Sammon saw an attempt blocked after peeling off his marker to hunt down Reed's long pass.
Neill Collins failed to direct his header on target after meeting Martyn Woolford's corner, soon after the former Millwall midfielder had seen Lainton parry another attempt away.
But Adkins, flanked by Andy Crosby and Dean Wilkins on the touchline, will have been slightly concerned that the action was becoming increasingly loose with Bury granted several promising situations to build upon as United tried to press.
His fears proved founded when Pope fired them in front just past the hour mark with a decisive finish after Danny Mayor's shot had provoked a penalty box scramle. Mark Howard, who had been powerless to prevent the goal, foiled Leon Clarke with his legs soon after as Bury's theatrics continued and their confidence grew.
Sharp, though, sucked it away with 20 minutes remaining when he levelled in front of The Kop. Kieran Wallace, who had been introduced at the expense of Reed, beat both Riley and Brown with a deft turn and was hauled down to win the penalty which his colleague converted.
Riley redeemed himself with a breathtaking goal as time ebbed away before Clarke sealed the points for the visitors by chipping Howard who had been left horribly exposed.
Sheffield United: Howard, Freeman, Basham, Sharp, Collins, Woolford (McNulty 82), Sammon, McEveley, Campbell-Ryce (Flynn 60), Reed (K Wallace 60), Edgar. Not used: Scougall, Alcock, Higdon, Long.
Bury: Lainton, Riley, Hussey, Tutte (Brown 38), P Clarke, Mellis (Pugh 70), L Clarke, Mayor, Jones (Pope 57), Soares, Cameron. Not used: Dudley, Rose, Ruddy, Foulds.
Referee: David Webb (Lancashire).