The Hornets went down 3-2 at Kingsmeadow in their first senior outing of the summer, shipping all three goals in the second half of the match.
Silva has brought in five new faces since replacing Walter Mazzarri as head coach earlier this summer, most recently landing the signature of Nathaniel Chalobah from Chelsea on a permanent basis, but he is now keen to further bolster before the August 31 deadline.
"What we saw is what I expected. The result is not good for us, but normally in a pre-season game the result is not as important as the performance of the team," the Watford Observer quotes him as saying.
"In this type of game we want to see how the players understand our ideas. We need to improve as a team and put in some hard work. I saw a little bit of what we are trying in the first half and how we reacted after the second goal, but I didn't like how we started the second half and we lost our focus too easily.
"The number of signings is not the most important things, but Gino (Giampaolo Pozzo) the owner and Filippo [Giraldi, sporting director] knows the positions we need and what I want for a team, and we need to work hard in the market to improve our squad.
"I don't want to talk about positions, I respect our players too much. We want to improve our squad, but we have good players who have worked hard over the past two weeks to show me their quality."
Watford are back in action on Tuesday evening when taking on Viktoria Plzen, before games against Eibar, Aston Villa and Real Sociedad.