City have been heavily-tipped for the title and have a considerable strikeforce themselves, including Sergio Aguero, Carlos Tevez, Edin Dzeko, and Mario Balotelli, but the Italian said that he believes United will be the team to beat "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."
United boss Sir Alex Ferguson drew parallels with his current four strikers - notably omitting Dimitar Berbatov - and his legendary treble-winning 1999 team, and Mancini believes that they could lead United to a 20th Premier League title, saying: "I think it is the best four strikers in the world.
"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."