He joins a forward line that already includes Wayne Rooney, Danny Welbeck and Javier Hernandez, and which as far as Mancini is concerned, is unparalleled at the moment.

“I think it is the best four strikers in the world,” Mancini – who has the considerably potent striking quartet of Sergio Aguero, Carlos Tevez, Mario Balotelli and Edin Dzeko at his own disposal – said.

“Last year our four strikers did better than other strikers, but we need to work harder than last year because this year United, with Van Persie, are better.”

The capture of last season’s Golden Boot winner Van Persie represents a bold statement of intent on the part of United manager Sir Alex Ferguson, who is on a mission in 2012-13 to reclaim the Barclays Premier League crown his side were pipped to in dramatic fashion by their derby rivals City in May.

Last Friday Mancini labelled Ferguson’s men as favourites to win the title this term, and speaking a week on at a press conference to preview City’s league campaign-opening home clash with Southampton on Sunday, he made it clear his feeling on the matter had only grown stronger.

Asked if it was even more so the case that United should have the favourites tag with Van Persie among their ranks, Mancini said: “Yes, for sure, and I was serious when I said this last week because United have played for the title always, every year for 20 years.

“Although we won the last championship, we can’t change this in one year.

“For this reason, I think they are favourites for the title, and now they have Van Persie.”

Questions have been raised over the reported £24million fee for Van Persie, who is 29 and has suffered with injury problems in the past, but Mancini is in no doubt that United are better off for having the Holland striker.

He said: “I think Van Persie is one of the best strikers in the world. I am sure they are better with him. Anybody who bought him would be better.”

It was felt Mancini wanted to sign Van Persie himself, although he claims it was not a realistic possibility.

“I felt he was going to stay at Arsenal or sign for another team, but not us,” he said.

“We already have four strikers. It was impossible for us to sign another one.”

The one player City have recruited this summer is England international Jack Rodwell, who could be set for his debut in Sunday’s game, a week after his transfer from Everton was announced.

Last Friday Mancini had said he was “not happy” that his efforts to strengthen his squad up to that point had been frustrated, adding: ”You have to speak to our sporting director (Brian Marwood), not me.”

But after Rodwell’s official unveiling yesterday, the Italian insisted he had no problem with Marwood and expressed his optimism that City would do further business before the end of the transfer window.

“What I said last time was not because I had a problem with Brian – I don’t,” Mancini said.

“But when you are a manager, you want maybe sometimes to buy a player quickly. At the same time I know it is difficult because the market is difficult.

“It was important to start with one (signing) and now it is important to think about the game on Sunday.

“Then we have about 10 days until the end of the market and I think we will do (more business) – I am sure.”

Mancini suggested there was little chance of City signing defender Daniel Agger from Liverpool or midfielder Daniele De Rossi from Roma, and when asked about Athletic Bilbao’s Javi Martinez, the manager said: “We talked about Martinez with the club, but this is another situation which is not easy because there are three or four top clubs who want him. But we have 10 days.”

Rodwell, who Mancini regards primarily as a midfield option but also as a possible one in central defence, has struggled with hamstring problems in recent times and his new boss will run the rule over him in training before deciding the extent of the 21-year-old’s potential involvement against the Saints.

Mancini will also assess the fitness of goalkeeper Joe Hart, missing from last Sunday’s 3-2 Community Shield victory over Chelsea due to a back complaint, while defender Micah Richards (ankle) and midfielder Gareth Barry (abdominal problem) are definitely ruled out.

Meanwhile, City have confirmed Ferran Soriano as their new chief executive.