In a bone-cruncher of a match, both these sides gave clear indication why new year spending is a must if they are not to flirt with relegation. A rare moment of class inspired by Hatem Trabelsi and completed by Stephen Ireland was enough to make City somewhat unworthy winners.
"I was pleased with our resilience, but not our performance," admitted a realistic Stuart Pearce. "The position we're in we'll have to scrap like that for the remaining 18 games. We've got so much more ability in that dressing room than we're showing."
Following Saturday's home defeat by Bolton, Pearce dropped three players, whereas Neil Warnock felt sufficiently positive about his side's showing against Portsmouth to stick with the same line-up for the fourth consecutive game.
The opening exchanges were frantic, in the "all-hell-and-no notion" sense. Paddy Kenny did well to defend a ball which took a wicked bounce and hit him in the face, while Nicky Weaver touched two stunning drives past the post - from Stephen Quinn and Phil Jagielka respectively.
United had a fair shout for a penalty too, but the referee, Mark Clattenburg, adjudged it was ball to Micah Richard's hand rather than vice versa.
While City's confidence was brittle, United exhibited work rate and physicality - both have seen them avoid the bottom three.
However, by the half-hour Joey Barton was assuming the kind of maverick role that caused problems for the hosts. When allied to Richards' heading skills, only an unnoticed handball on the line by Rob Kozluk kept City out.
In another rare upfield City sally, there could be scant excuse other than the acute angle for Georgios Samaras' miss, especially with chances almost as rare as Christmas snow.
As Jagielka's influence grew, Barton's diminished and, in a goalmouth mêlée, Samaras made up for his earlier miss by heading a Jagielka effort off the line.
When Trabelsi carved City's winner out of absolutely nothing, it was Samaras who chested down his diagonal ball for the unchallenged Ireland to find the far corner of Kenny's net.
Pearce agreed that the right man had scored. "I've been trying to encourage him to shoot rather than pass. I want him to be more selfish so he can be a full part of the Premiership scene."
United had no option now but to chase the game and as a result gave City the unknown luxury of space. But the Blades lost their moment as well as their shape and City showed what they could do with some flowing passing utilising the width of the pitch.
Warnock was adamant that "the game has given us a lift. We could have won by three or four goals today. It showed we have nothing to fear. I can't think of anything Paddy had to do other than pick the ball out of the net."
But perhaps he was being generous in claiming "if I didn't get another player this season, I still think we'd have a fighting chance".
Goal: Ireland (78) 0-1.
Sheff ield United (4-4-2): Kenny; Kozluk Davis (Bromby 68),Morgan Geary ( Armstrong 26); Gillespie, Tonge, Jagielka, Quinn; Hulse, Webber (Nade76). Substitutes not used: Quinn, Richards.
Manchester City (3-5-2): Weaver; Richards Dunne, Onuoha (Jordan 85); Trabelsi, Ireland, Barton, Dabo, Distin; Vassell (Miller 90), Corradi (Samaras HT). Substitutes not used: Isaksson, Beasley.
Referee: M Clattenburg (Durham).
Booked: Sheffield Barton, Morgan.
Man of the match: Ireland.
Attendance: 32,591.Reuse content