The Spanish schemer collected his fourth Premier League winners' medal as a City player earlier this month after a titanic title battle with Liverpool, who finished just a point behind Pep Guardiola's side on an incredible 97 points.
The Reds had been well clear of the Citizens at the turn of the year and could have moved 10 points ahead had they won January's showdown at the Etihad Stadium.
However, goals from Sergio Aguero and Leroy Sane handed City a 2-1 victory and Silva believes that was the moment in the title battle in which the momentum started going in their favour.
"It was a difficult game, and it was also a key game," Silva told CityTV. "At this point we couldn't afford to lose otherwise the league would have been for them. But we managed to win, it was a very important match."
The 33-year-old, who singled out Bernardo Silva, Aguero and Vincent Kompany as City's star men this season, went on to say that this had been the toughest Premier League campaign he has experienced in nine years at the Etihad.
"It is definitely one of them because to get so many points to become champions means that it has been a very competitive league and it was all worth it," he added.