The Catalan giants are expected to rest several of their stars for the match with the Segunda Division 'B' side, but Vilanova believes that their opponents' solid defence will ensure a tough two-legged match.
Vilanova told reporters: "We have to give this fixture the importance it deserves. I'm going to approach this cup tie with the most competitive team possible to get a good result.
"I don't see this as an opportunity to give players that haven't had a lot of playing time more minutes on pitch. However, it is true that we have quite a few players who are recovering from injuries.
"I know their coach very well and I know how he works. Alaves have only conceded four goals in their last 10 matches. This means their defence is well worked and organised."
Barcelona currently share the lead in La Liga with Atletico Madrid.