Such is the embarrassment of riches in east Manchester, you make the trip bracing yourself to be outpassed, outshot or outdribbled, but the Blades were undone when the brilliant John Fleck ran into referee Chris Kavanagh.
It spoke volumes that with ten minutes to go Kavanagh was threatening to book Sergio Aguero if the Argentinian centre-forward did not take the quick route off the pitch to be replaced by midfielder Phil Foden.
The Blades had given their exalted hosts a real fright but for the first time since January 19, they were beaten away from Bramall Lane. Minutes after Aguero’s withdrawal, Kevin De Bruyne confirmed as much with a brilliant finish from a counter-attack he started.
That was was ironic because at 0-0, all the counter-attacking threat had come from the Blades. To be as good as Chris Wilder’s side is on its travels, being brilliant on the counter-attack is non-negotiable, but to beat Manchester City you often need more than just that.
Sheffield United also had a counter-attack goal disallowed by the barest of video assistant referee margins. They might have known then it was not going to be their night.City had plenty of the ball, but were doing little with it until Kavanagh inadvertently opened the door for them.
Then, Fleck went chasing an Oliver Norwood pass and collided with Kavanagh, taking him out of the game and giving De Bruyne the space to pick out Aguero. As usual, his finish was unerring.
VAR took a look, but as the ball had not touched Kavanagh, there was nothing that could be done to chalk the goal off.
Even though there were only 52 minutes gone, even though the Blades had shown such a cutting edge on the counter, and even though they would later hit the inside of the post with a brilliant Billy Sharp header, you felt at that stage Sheffield United’s hugely impressive unbeaten run was doomed, and so it proved.
It had looked quite promising up to that point.
Manchester City, as is their way, had plenty of the ball in the first half, without working Dean Henderson. Sheffield United, by contrast, had a goal disallowed and looked dangerous whenever they sprang a counter-attack.
Top-scorer Lys Mousset was back in the starting line-up, but his shooting was not sharp enough to put his side in front at the break – at least not when the technology intervened. He glanced an eighth-minute header wide from a cross by Callum Robinson, making his first start since October as Chris Wilder shuffled his pack in an attempt to keep the Blades sharp during a typically manic Festive period.
Fernandinho had to make an important block when Mousset robbed Oleksandr Zinchenko, and John Egan headed Oliver Norwood’s cross wide.
Mousset had the ball in the net after half an hour. Fleck played an excellent curling pass for the centre-forward to run onto. He put the ball in the net, and waited to see what the video assistant referee made of it.
Way clear of his marker Zinchenko, Mousset was a big toe behind last defender Eric Garcia. VAR measures offside decisions with a precision the technology is not up to. It was, according to the lines on the screen, a correct decision but as so often in Sheffield United matches this season, supporters vented their anger about interference from Stockley Park.
The Blades were growing in confidence, perhaps realising how ineffective their hosts were proving despite their huge quality.
An outstanding ball from Jack O’Connell released Enda Stevens, but when the Irishman crossed, Mo Besic, making his full Premier League debut in place of the injured John Lundstram, volleyed wildly over.
United kept plugging away, Fleck finding himself in a tight spot but picking out Norwood, whose first-time ball sent Mousset galloping into space again.
One-on-one with the goalkeeper, he was pushed into a tight angle and when he found the net with the outside of his boot, it was from the wrong side.
City of course had moments of brilliance too, and the pass Rodri slid into Riyad Mahrez was as good as Fleck’s, but the winger’s twisting and turning was not enough to shake off John Egan. The centre-back also stopped a dangerous De Bruyne dribble in its tracks.
When Chris Basham’s back touched a goalbound Raheem Sterling shot wide, Kyle Walker blazed his shot from the corner.
Besic started the second half by rattling the stanchion after another ball over the top to Mousset, but Kavanagh and Aguero quickly took the wind out of their sails.
After it, Henderson even had a shot to save, although De Bruyne’s shot did not require Henderson to move.
There was no bursting of the floodgates, even if Egan did need another excellent tackle, this time on England international Raheem Sterling, and a Mahrez shot struck O’Connell and bounced to safety.
De Bruyne put the result out of doubt in the 83rd minute, picking the ball up deep, and exchanging a one-two before finding the net with a quality finish.
Even Sharp, on as a late substitute, could not catch a break, arching his neck brilliantly to a Stevens ball in the first added minute of stoppage time, only for his header to come off the inside of the post with Claudio Bravo beaten.
Manchester City: Bravo; Walker, Fernandinho, Garcia, Zinchenko; Rodri; Mahrez, De Bruyne, Bernardo Silva (Gundogan 62),Sterling (Jesus 88); Aguero (Foden 80).
Unused substitutes: Mendy, Cancelo, Otamendi, Carson.
Sheffield United: Henderson; Basham, Egan, O'Connell; Baldock, Besic (McBurnie 75), Norwood, Fleck, Stevens; Robinson (McGoldrick 59), Mousset (Sharp 84).
Unused substitutes: L Freeman, Jagielka, Verrips, Osborn.
Referee: C Kavanagh (Lancashire).