Former Manchester United defender Silvestre said: "You have got to learn and learn quickly. You have not got many opportunities to reach a quarter-final of the League Cup and they have to learn that we should have won here.
"Just a lack on concentration on two occasions cost us two goals."
But he added: "I think they have progressed really well. Hopefully they can prove something in training and they get the chance in the first team."
Silvestre added: "A win against the big four is important for the confidence. That proves we can still compete for the title. Everybody knows we slipped too many times this season and we have to get some consistency.
"The league is really tight and if you drop 10% of performance the other team can beat us. The Premier League is tough and any team can beat any team."