The £24million summer signing has endured a slow start to life at City, his integration to the Premier League not helped by his late return from the World Cup and two lengthy international trips to Mexico and Argentina.
However, starting Thursday night's Europa League encounter with Salzburg in Austria, Silva netted the early goal that sent the Blues on their way to a comfortable 2-0 win.
And Mancini believes it will be the first of many.
"David is the fantastic player, and for him it is a different situation now," said Mancini.
"He is playing a different kind of football. But after one month, he is ready to go 100% for the team.
"He will be an important player for the future. He is a strong player who played for Valencia in the Champions League for many years."
Mancini denied Silva was too small to make an impact in England, even though his diminutive frame does appear more suited to the European style.
The Italian continued: "He knows how to play football. Arsenal have two or three players like David and they play very well.
"David can play in every position. For Valencia he played either right or left wing but I think this position (behind the striker) is the best for him."
Mancini also had words of praise for Brazilian forward Jo, who on his first City start since December 2008 scored only his fourth goal for the club to seal a victory which leaves the Blues top of Group A ahead of the visit from Italian giants Juventus in two weeks.
"For strikers it is important to score goals," said Mancini.
"Jo has scored an important goal and I hope he continues to play like he did tonight.
"We are talking about two important players. For me my players are the best players in the world."
Salzburg coach Huub Stevens refused to discuss City's performance, or their status as tournament favourites.
However, he did admit his side underperformed on Thursday night.
Stevens said: "We did not start very well, and if you are not on top of your game in the first 10 minutes against a team such as Manchester City, it is always going to be a struggle," said Stevens.
"We gave City too much space, and they had too much room to get at our defence."