Mancini guided City to Premier League and FA Cup success before being sacked last May.
Under his successor Manuel Pellegrini, City have gone on to become one of the most exhilarating sides in Europe.
City have scored 106 goals already this season and they remain in contention to win four trophies.
Roberto Mancini: "I'm happy with what I did in Manchester.
"I'm happy that now Manchester City is one of the best teams in England because I built this team.
"I am very happy with all these players. I am happy with my job and I love Manchester City supporters. I had a fantastic experience.
"The players that score the goals are players that I bought - (Sergio) Aguero, (Edin) Dzeko, Yaya (Toure), (David) Silva, (Samir) Nasri.
"I think Pellegrini is doing a good job but what Manchester City is doing now we did three years ago. It's the same.
"I never lost the trust of the dressing room.
"This is all the stories that someone from inside got out, but this is not true.
"After four or five years, maybe the manager needs to change team.
"I did my job, I built a fantastic team, we played fantastic football and we didn't win last year because Manchester United bought (Robin) Van Persie.
"Van Persie was the difference last year. If not (for him) I think in these three years we would have changed the history in Manchester because we played really good football and now they are continuing to do this.
"When you work, you can have some problem with the players. This is normal because the manager always wants the players to work hard, play well and the players should understand this."