The Blades, reduced to ten men at the closure of half-time battled hard in the second half and were rewarded with a two-nil victory against the Tigers who were second in the league at the start of play.
At the stroke of half-time captain Chris Morgan was handed a second yellow card after pulling back Fraizer Cazmpbell in front of goal, United responded by brining on Ugo Ehiogu and after the break took the lead when young Stephen Quinn volleyed home.
And the Blades doubled there advantage when James Beattie fired home from the penalty spot shortly after Billy Sharp was fouled in the box by David Livermore.
Captain Chris Morgan is now suspended and will sit out the Blades final two games of the Championship season, with former Aston Villa and Glasgow Rangers defender Ugo Ehiogu likely as his replacement.
Blades boss Kevin Blackwell is likely to field David Cotterill against his former club; the winger on loan from Wigan Athletic started his career withy the Robins as an apprentice - making his debut in October 2004 against Colchester United (0-0).
In a career which spanned two years as a professional with City he made no less than 51 (+15) starts for the club and netted his first of nine goals in a 7-1 defeat at Swansea City before making a £2,000,000 move to the JJB Stadium in August 2006.
Possible Blades Line-Up: Paddy Kenny, John Halls, Ugo Ehiogu, Matthew Kilgallon, Gary Naysmith, David Cotterill, Michael Tonge, Gary Speed, Stephen Quinn, James Beattie, Billy Sharp.
Bristol City slumped out of the automatic zone and replaced by Stoke City after their 2-1 defeat at the Britannia Stadium last Saturday night. Former Gillingham striker Mamady Sidebe netted twice to hand the Potters a two goal lead before veteran Dele Adebola nabbed one back for City.
The Robins will travel to Bramall Lane without Jordan Walker (knee) whom remains a long term injury whilst Steve Brooker (hamstring) and Lee Johnson (ankle) are also expected to be excluded from the squad due to injury.
City boss Gary Johnson told BBC Radio Bristol; "The whole squad will be travelling because it could only be two games left of the season but it could be five, so everybody's got to stay tuned in to what we're doing.
"Sheffield United have a similar sort of group to when we played them here [at Ashton Gate], they've got our old player David Cotterill on loan from Wigan and he's supposed to be doing quite well.
"You don't know until the day but it's whatever team turns up in our colours, if I can get a team out there and pick the right team for the right game we hopefully will come out victors."
Possible Robins Line-Up: Adriano Basso, Bradley Orr, Lewis Carey, Jamie McCombe, Jamie McAlister, Brian Wilson, Marvin Elliott, Cole Skuse, Michael McIndoe, Dele Adebeola, Darren Byfield.
:: Man in the Middle ::
Referee: Mark Halsey
Assistants: A. Garratt & C. Sarginson
Fourth Official: N. Miller
- 14.03.1998 - Blades 4-0 Reading
- 26.12.1998 - Birmingham 1-0 Blades
- 03.04.1999 - Barnsley 2-1 Blades
- 28.08.1999 - Blades 2-2 Ipswich
- 30.09.2000 - Blades 1-1 QPR
- 18.08.2001 - Blades 0-0 Gillingham
- 09.11.2001 - Wimbledon 1-1 Blades
- 19.01.2002 - Blades 0-0 Nottingham
- 28.09.2002 - Blades 1-2 Watford
- 23.08.2003 - Blades 1-0 Norwich
- 20.08.2004 - Preston 0-1 Blades
- 15.04.2005 - Blades 0-1 Derby Co
- 29.10.2005 - Blades 0-0 Cardiff City
- 01.01.2007 - Middlesbrough 3-1 Blades
- 17.03.2007 - Chelsea 3-0 Blades
- 18.09.2007 - Blackpool 2-2 Blades
- 27.11.2007 - Charlton Athletic 0-3 Blades
- 19.01.2008 - Sheffield Wednesday 2-0 Blades