The quadruple is still on. In truth, it was never off, despite the laboured start to the night. When Alvaro Negredo takes to this pitch his presence comes with a guarantee. For all but the last attack of the opening half Manchester City were a team lost in sparring, an approximation to the threshing machine they have become at the Etihad.
That is until Negredo hit the turbo button. A header at the close of the first half and a stabbed second two minutes into the second took his tally at the Etihad to 16 this season, chalked up in all of a dozen matches.
Blackburn Rovers had done a half decent job of frustrating City, and in Tom Cairney had a player in the middle of the park who stood comparison with those in blue, but once the red wall had been breached it was always going to be a numbers game.
Edin Dzeko flashed in a third in the 67th minute, turning in a cross from Jesus Navas at the near post. On the touchline Sergio Aguero warmed up, a cruelty the Championship side did not deserve. It was Negredo who made way for the Argentine predator with 18 minutes to go. Aguero was unusually slow to make an impact, allowing just 50 seconds to pass before swivelling in the box and planting his 20th goal of the season past Simon Eastwood, on at half time for Paul Robinson.
It was not over yet. Dzeko helped himself to a second, a carbon copy of the first, to take City to 99 goals in all competitions this season. Much more of this and City risk being taken to the Competition Commission.
In pictures: Manchester City 5 Blackburn Rovers 0
In pictures: Manchester City 5 Blackburn Rovers 0
1/6 Manchester City 5 Blackburn Rovers 0
DJ Campbell attempts to block Costel Pantilimon's clearance
2/6 Manchester City 5 Blackburn Rovers 0
Alvaro Negredo goes to pick the ball out of the net after scoring City's opener
3/6 Manchester City 5 Blackburn Rovers 0
Micah Richards tries his best to get on the scoresheet with a diving header
4/6 Manchester City 5 Blackburn Rovers 0
It didn't take Sergio Aguero long to add City's fourth
5/6 Manchester City 5 Blackburn Rovers 0
Sergio Aguero (centre) celebrates scoring in Manchester City’s 5-0 FA Cup win less than a minute after coming on as substitute
6/6 Manchester City 5 Blackburn Rovers 0
Edin Dzeko completed a rout with his second of the night
At the back end of the last century, in another football world, Blackburn Rovers briefly occupied the City slot, bankrolled by a steel magnate and dominating the agenda. Jack Walker's millions would barely settle the tip on a night out with the oil barons fuelling City's identity shift today. Week by week, goal rush by goal rush, City are acquiring their own mystique and with it power.
The City messaging had been doing its work all week in the hearts and minds of Blackburn. For their manager, Gary Bowyer, this was an opportunity for his players to breathe the same air as giants, to associate with a species of footballer from another dimension. Whatever it is City do, it is beyond the common experience at Ewood Park, so the legend goes, something to be savoured, an honour to share.
They were probably disappointed at the absence of City's premier creative hub, Yaya Touré, David Silva and Samir Nasri, denied the chance to tell their grandchildren what it was like to be flayed at the Etihad by the best in the land. Never mind Aguero, Negredo and Navas would have to do.
The Blackburn players had an extra 10 minutes to take in the riches courtesy of a delayed kick-off to accommodate the last days of Hayley Cropper on Coronation Street. There is no end to the pulling power of that fiction in this parish. Hayley is still with us, but for how long?
As they made their way to the changing rooms the Blackburn players wore the same wide-eyed expressions as the schoolkids on a tour of the Etihad media suite. Outside a band played in City Square. My, how far the sheikhdom has come from the Kippax.
The Blackburn fans shared none of the deference displayed by their team. "Where were you when you were shit?" they inquired of the Etihad citizenry. City's second string, eight changes from the win at Newcastle, made us wait two minutes for a crack at goal, a header from Dzeko. Mind you, Blackburn did not touch the ball in all that time.
Dzeko went close again in the 10th minute cracking a venomous right-footer over the bar. Blackburn sat deep, City pinged the ball left and right, their authority uncontested. Milner, captain for the night, even indulged in a stepover in one break down the left.
City were momentarily discomfited in the 17th minute when Richards slid in to concede a corner. Nothing came of the novelty and City quietly resumed control of the ball. The only element missing was urgency, too many floated crosses from the wings serving only to keep Robinson warm in the Blackburn goal.
Manuel Pellegrini rushed to the technical area to wave his team forward and was rewarded with a piledriver from Javi Garcia that Robinson could only palm away, fortunately for Blackburn to a red shirt.
As the half drew to a close the scoreboard revealed a possession rate of 74 per cent in City's favour. That was nil comfort to an audience that has witnessed half a century of goals already this season.
Help was at hand in the shape of Negredo, who met a cross from Fernandinho in the manner of a mallet hitting a tent peg, cracking the ball hard and low into the back of the Blackburn net with his head on the stroke of half-time.
Man of the match Negredo.
Match rating 7/10.
Referee C Pawson (S Yorks).
Revised FA Cup fourth-round draw
Friday 24 January
Arsenal v Coventry (7.45pm)
Nottingham Forest v Preston (8pm)
Sat 25 January (3pm unless stated)
Bournemouth v Liverpool (12.45pm)
Birmingham v Swansea
Bolton v Cardiff
Huddersfield v Charlton/Oxford
Manchester City v Watford
Port Vale v Brighton
Rochdale v Sheffield Wednesday
Southampton v Yeovil
Southend v Hull
Sunderland v Kidderminster Wigan v Crystal Palace
Stevenage v Everton (5.30pm)
Sunday 26 January
Sheffield United v Fulham (1pm)
Chelsea v Stoke (3.30pm)