Capello was proud of Roberto Mancini over his title success with City last season.
But he warns: "Mancini has done a great thing last season because beyond the daring finale, and I speak of the injury time on the last day, they also made up the eight points lost by United in a month, City deserved to win the Premier League. They played better.
"The signing of Van Persie by Ferguson however has changed everything, because the Dutch is one that scores goals and we've seen this immediately.
"Moreover Mancini has lost De Jong, and there is not a substitute who came he wanted."