The prolific Dutchman was heavily linked with the Barclays Premier League champions before opting to sign for rivals Manchester United in a reported £22million deal. Mancini has previously admitted he was interested in signing the 29-year-old but has only now indicated how strongly City pursued him.
The Italian said: "We wanted Van Persie because we knew he could be an important player. He is totally different from our other strikers. We wanted him for the Champions League and for the Premier League. We were very close."
He added: "We were sure he was for us but this did not happen and now we can do nothing. We were very close three or four months before he joined United."
Van Persie, who scored 37 goals for Arsenal last season, sparked a scramble for his services when he revealed he would not be renewing his contract at the Emirates Stadium.
When he was unveiled as a United player in August he said he had listened to the "little boy" inside him when making his choice of club.
Mancini said he knew why City failed in their bid but would not give a reason. When asked if it related to money, Mancini said: "It is not the problem."
Van Persie has hit the ground running at Old Trafford and has already scored 17 times for United in all competitions.
With United beginning 2013 with a seven-point lead at the top of the Premier League, Mancini believes Van Persie is the key difference between the two sides from last season.
He said: "I think Van Persie, for United, is an important player. It is clear he changed this situation. In this moment, the difference is this."
- Sports & Recreation
- Manchester United
- Barclays Premier League