The Italian believes that the North-West outfit conducted themselves all wrong in the market at the end of last season, resulting in their failure to clinch Robin van Persie, who ended up signing for rivals Manchester United.
"You should move very quickly," Mancini said in a press conference. "We didn't do this last year. We moved so slowly. We lost the players that were our targets to improve our team."
Despite losing this season's Premier League title to the red half of Manchester, they could still end the campaign with a trophy if they defeat Wigan Athletic in the FA Cup final next month.