The blue half of the city are currently 12 points ahead of their local rivals in the Premier League table.
However, United have been buoyed by their recent result against Olympiacos, which has placed them in the quarter-finals of the Champions League.
"First thing, we have to think of Saturday, but a derby is a derby," BT Sport quotes Silva as saying. "At the moment we are better but in any derby anything can happen.
"So, we just have to go out and win the matches. It's a derby but the powers [in the city] don't shift in derbies. We have won [at Old Trafford] the last two years, and hopefully this will be the third one."
Before Tuesday's encounter, City will go up against Fulham at the Etihad Stadium.