The Camp Nou side lost 2-1 to Ajax in Amsterdam last month and will host Neil Lennon's side in the final game of Group H.
Barca do so having come under increasing pressure after losing their last league match to Athletic Bilbao. The Catalans are now in need of a convincing result against Celtic to make sure they go into the last 16 of the Champions League as section winners.
Xavi appears to have recovered from injury in time to help his side return to healthier form - he was rested in Friday's 4-1 Copa del Rey win over lower league side Cartagena - and is not inclined to allow his team-mates to kick their heels against Celtic. Rather, he was urged them to take charge of games with their trademark style.
"The game against Ajax is what we must not do again," said Xavi. "I think it is the biggest mistake we have made. In Bilbao, we could easily have won. I didn't enjoy the Ajax game. When opponents have a tight defence, we can find it hard to get spaces to score and create.
"We have to improve in terms of mobility and confidence and recover some of the things we do automatically as well as getting ball back quickly. We want to control our matches again. We accept criticism and we are working to play better and make sure people feel proud again of this Barca."
The Catalan media have not been quite so taken with Argentinian coach Gerardo 'Tata' Martino, either. Barca remain top of La Liga ahead of Atletico Madrid - albeit on goal difference - and have already secured their place in the knockout stage of the Champions League. However, Tata's Barca have not played their way into the hearts of the local media in the same way that Pep Guardiola's teams did; establishing a more direct way of playing as well as a rotation system aimed at getting his senior players through the season relatively unscathed.
"Perhaps we are finding it harder to have ball and that could be connected to playing such direct football," said Gerard Pique, the Barca defender. "[But] I have maximum confidence in this team."
Barca will intend to personify that bullishness tomorrow night when they face Celtic. They have bridled at the criticism which has followed defeats by Ajax and Bilbao, with Alex Song last night adding to the chorus of players who plan to use the visit of the Scottish champions to get back in tune. "We have a lot to prove after the last Champions League match," said Song. "We have to show that we are the best team in the world and win every game."