Silva believes United's attack has benefited from the arrivals of Bryan Mbeumo and Matheus Cunha.
Ahead of Sunday's clash, the Fulham manager said: “Big one. We are playing against a great side.
“I know that last season was not what they wanted. Definitely, was below their standards, below the size of the club and all that stuff, (but) they are the first ones to recognise that.
“Last season, they had a lot of great players. This season, they kept almost all of them. And until now, they have been able to spend heavily in the market on some players.
“Two they signed from Premier League (sides) – the number of goals they scored, and how they were important for the teams they played for… And they signed a striker that all the market was looking for.
“The club is Man United, a club that already spent more than £200m, and probably are going to spend more. It's going to be a big clash, in my opinion, great game for us.
“Very important for us, like it's very important for Man United, and it's going to be another very demanding Premier League game, like normal.”