José Mourinho has just described Manchester City as title favourites, with a squad so powerful it puts them in a different dimension to everyone else.

Their goals tally is certainly in a different dimension to everyone else's. Their three strikers scored five between them here, including one from the returning Sergio Agüero with virtually his first touch, to take the total for the season to a staggering 99.

Manuel Pellegrini has promised to try to win all four available trophies – no one else in England is in a position to say that – and after the 6-0 victory over West Ham that virtually gives them a bye to the first final of the season no one bothered to snigger. Not even Manchester United fans, in fact especially not Manchester United fans, for if Sunderland can be overcome in the second leg of the Capital One semi-final they know exactly which free-scoring side they will be facing at Wembley.

This was the FA Cup, perhaps only the third most important of City's priorities this season, and after complaining of having to play every three days Pellegrini refreshed his squad so thoroughly Micah Richards got his first game in more than a month. Yet if Blackburn had been hoping to meet some sort of shadow side, a collection of kids and reserves, they were sadly disappointed. True, Vincent Kompany was given a rest, but Joleon Lescott and Matija Nastasic is hardly a makeshift centre-back partnership and as with the goalkeeper, Costel Pantilimon, Pellegrini was simply keeping faith with the players that started at Ewood Park.

David Silva was the only high profile starter from the first game who was left out, though with Jesús Navas a capable deputy and Agüero poised to make his comeback after injury from the substitutes' bench, City could neither be described as weakened or vulnerable. Pellegrini is clearly a man of his word, although Mourinho also happens to be right. City have a squad of such depth it would be quite difficult to field a substandard side, and Agüero's goal within seconds of taking the field merely underlined how irrepressibly the team is performing at the moment.

The only thing that might have offered Blackburn encouragement was that Álvaro Negredo and Edin Dzeko did not form a particularly effective strike partnership in the first game, despite all the goals they have hit since.

That theory held good for the first half hour or so, with Dzeko first firing over from Negredo's pass, then almost hitting the top tier of the stand with a first-time effort from a Navas free-kick, and began to look almost promising when Navas delivered a precision pass along the face of goal and first Negredo and then Fernandinho slid in fractionally too late to make contact.

The only flaw in the logic was that the longer the stalemate continued the more tempted Pellegrini would be to throw on Agüero, and that possession statistics 75-25 in City's favour meant it was unlikely Blackburn would be able to hold out all night.

In the event, once the deadlock was broken City's strikeforce ended up filling their boots again. In an almost exact repeat of what had happened at Blackburn, Negredo popped up with a goal in first-half stoppage time. Navas played in Fernandinho on the overlap, with both Dzeko and Negredo waiting in the area he could hardly miss both of them, and though the cross sailed over the former the latter was in too good a position to miss his 20th of the season. Within two minutes of the restart he had moved his total on to 21, thanks to Aleksandar Kolarov's sumptuous pass, and City were well on their way. In the first game they got their noses in front only to concede early in the second half, but once Negredo had applied an expert finish to a ball played behind the Blackburn defence there was never any doubt about the outcome.

The only question as the goals piled up in the second half and Dzeko matched Negredo's contribution to the scoresheet, was whether City would reach their century for the season. The Cardiff manager, Ole Gunnar Solskjaer, will be delighted to hear that City go into Saturday's league game at the Etihad Stadium needing one goal for three figures.

Negredo's finishing prowess has been a major plus for City this season. With an incredible 16 goals in his last 12 home games he is arguably the most impressive of Pellegrini's summer signings, even if City remain heavily reliant on a quartet of players who were here when the Chilean arrived. Silva and Agüero provide imagination and a touch of the unexpected, Kompany a sureness and reliability at the back that any defensive combination without him seems to struggle to reproduce, and Yaya Touré brings an energy and drive to keep it all moving forward.

Take a quartet of such quality out of most sides and they are bound to notice the difference. City did, to an extent, but they are still in the hunt for four trophies, and they still have all four to come back.