Barca may be one of the most famous teams in the world but Vilanova felt the Catalan giants could still rely on a certain amount of mystery when they played in Europe - but not this week.
The main reason for that is Unai Emery, Spartak's Spanish coach.
Prior to moving to Russia this summer Emery spent five years battling in the Primera Division against all-conquering Barca, first with Almeria and then at Valencia.
Emery has not actually won any of his previous 14 showdowns with Barca but Vilanova concedes there is now little the 41-year-old will not know about the Blaugrana.
"Normally the advantage we have in Europe is that they don't know us as well as they do in La Liga, but in this case against Spartak that advantage disappears," said Vilanova.
Spartak, who also boast Spanish midfielder Jose Manuel Jurado in their ranks, have already shown Barca what they are capable of when they gave the four-time European champions a big scare at the Nou Camp in the opening round of the group stage.
On that occasion Spartak led 2-1 with less than 20 minutes to go, only for Barca superstar Lionel Messi to work his magic yet again with a late brace that earned his side a 3-2 victory.
Vilanova is expecting another tough clash, saying: "Like in Barcelona they will make things very difficult for us, they will be a very tough opponent and very well-organised in both attack and defence, such are the teams of Emery, who we know well."
Since beating Spartak at home, Barca have moved on to nine points in Group G, two clear of second-placed Celtic who they lost 2-1 to in the previous round.
If Barca had won that match they would have qualified for the knockout stages, but as things stand they still have work to do.
"We've got another opportunity now and if we don't achieve it (tomorrow) we will have to go and do it in Barcelona. But that's normal, the public thinks that it's an easy group and it isn't, not at all, all the opponents are very demanding."
Spartak prop up the group with three points but can still claim a top-two berth if results go their way over the final two rounds.
"The defeat in Glasgow has complicated things for the Catalans. It's going to be a tough game (tomorrow). In any case, our mission is to win," said Emery
"We will go out with this idea. We will try to take advantage of the chances that we'll have in the game."
Emery has a number of absentees for the clash at the Luzhniki stadium, with Romulo, Artem Rebrov, Diniyar Bilyaletdinov, Soslan Gatagov, Nicolas Pareja, Aiden McGeady and Artem Dzyuba all set to be missing.
Barca, meanwhile, travelled to Russia without injured quartet Adriano, Thiago Alcantara, Alexis Sanchez and Marc Bartra.