Jose Mourinho insists he is not on a revenge mission to dump Barcelona out of Europe.
Chelsea need only a point in the Nou Camp today to clinch a place in the knock-out rounds of the Champions League.
A win for the Premiership champions, however, will plunge the European Cup holders into a fierce qualification battle with Germans Werder Bremen.
Mourinho said: 'I'm not trying to help Werder Bremen to knock Barcelona out. That's not my fight.
'It's not knock-out. It's a group. We don't play to kick each other out of the competition. We play to progress.
'Our target is to finish first in the group and it's not my problem if it's Barcelona or Werder Bremen who finish second.
'We have three matches to get what we need to qualify.
'We know our last game is at home against Levski Sofia but of course I would prefer to qualify before the last game.'
Barcelona knocked Chelsea out of the competition last season and Mourinho stirred controversy on the eve of the latest showdown between the bitter rivals by Eidur Gudjohnsen had learned to dive since he left Stamford Bridge for Spain in the summer.
Gudjohnsen tumbled to win a very dubious penalty for Barcelona in a league game against Recreativo Huelva on Saturday and the issue is one of Mourinho's pet hates.
The Chelsea boss believes referees are intimidated at the Nou Camp into giving the home team penalties and the away team red cards and he called on Italian ref Stefano Faria to be strong tonight.
Mourinho is confident his new-look team are starting to fulfil their potential.
The 1-0 win at home to Barcelona, two weeks ago, boosted self-belief and expensive summer recruits Andriy Shevchenko and Michael Ballack are starting to show their true class.
Mourinho said: 'This season, we are a team with more experience.
'We can split our squad into two groups. One with high-level players with a lot of experience between 27 and 30, at a mature age who have adapted to the needs of big matches and big competitions.
'We have another group of young boys full of talent like Mikel and Kalou, working to be part of our vision.
'We have lost some good players from our squad but we are happy with the players we have.
'Everybody is improving and getting their form. The new people are ready to give more. Ballack is a good example of the way we are playing now.
'Last season we were a team who always played 4-3-3 but this season we are able to play different ways.
'We can play 4-4-2 or 4-3-3, with a diamond in midfield or two lines. We are more mature in tactical terms.'
Henrique Hilario will keep his place in goal after saving a penalty in Saturday's win at Sheffield United.
Hilario has only conceded one goal in four games since stepping in to replace the injured duo Petr Cech and Carlo Cudicini.
Cudicini is now fit but will have to settle for a place on the bench at the Nou Camp.
Mourinho will make a late check on the fitness of his strikers Didier Drogba and Shevchenko on Tuesday.
Both of them trained in the stadium on Monday.
Drogba showed no signs of the foot injury which forced him out of the game at Bramall Lane.
Shevchenko, who has been nursing a thigh injury, looked more restricted.
It was his first session with the squad for a week and he left the main group early to work on some sprints.
Salomon Kalou impressed on a rare start at Blackburn in the Carling Cup last week and is ready to step into the front-line if needed.
Kalou said: 'I am not afraid. It's good to have Shevchenko and Drogba and I have learned a lot from them. But I am ready to play whatever game and I will do my best.'