The Catalan giants have won their first three Group G fixtures and are five points ahead of Neil Lennon's side, who are one point ahead of Spartak Moscow and three ahead of Benfica.
A Barca win coupled with a Spartak defeat against Benfica will assure the Primera Division outfit of first place in the section.
Asked at the press conference at Celtic Park what would he would do if such a scenario unfolded, Vilanova, whose side have still to travel to Moscow before finishing with a home game against Benfica, replied: "It is probably the most important match in what is left of the year.
"If we qualify and are first in the group we will be able to rest some of our players and use the youth team."
When challenged on that policy later, in terms of it going against the spirit of competition and thus potentially harming Celtic's qualification chances, Vilanova gave Hoops fans some succour.
"I said the game was really important so that we could qualify and give some players a rest," he said.
"But do not worry, the teams that will play in the next games will always be top level because we have always been.
"The fact that some of those players don't play often doesn't mean they don't have an excellent level.
"But the most important thing is that we win tomorrow."
Vilanova refused to join those who criticised Celtic for their display in the 2-1 defeat in the Nou Camp last month, which saw Barca claim victory through an injury-time strike from Jordi Alba.
The Barca boss, who will give a fitness test to defender Gerard Pique who is battling to recover from a foot injury which has kept him out for seven weeks, said: "I don't know how they will play in front of their own crowd but they weren't that defensive really in the first game, they played really well.
"They played as we expected them to play, they were good at set-pieces and quick counters.
"It was really hard for us to beat them and we could only do that in the last minute.
"When you play against Barcelona they force you to defend close to your goal.
"But everyone is free to play the way we like and we were never comfortable or relaxed about it, we were always afraid of the counter-attack.
"So it will be very hard again tomorrow.
"I haven't been at Celtic Park before but I have heard a lot about the atmosphere, and we know how important it is to win."
Barca midfielder Alex Song, who featured for Arsenal in a Champions League play-off clash at Celtic Park in 2009, was certainly confident of victory.
"I played here three years ago, I know the atmosphere is very good," he said.
"But we are Barcelona and we are coming here to try to get a good result, to get three points.
"They (Celtic) just tried to defend at the Nou Camp but we kept playing because Barcelona do that, no matter what the score is and in the end we won.
"We know it will not be easy tomorrow but we will do our best to win because if we do we will go to 12 points."