I will not be surprised if Barcelona wins this match despite that head-to-head, they are the favorite. The secrete of winning Bayern and prevent them from scoring any goal has been revealed by Leverkusen and Aston Villa but I don't think that Barcelona will concentrate more on their defense because they're also a club that love dominating matches like Bayern. It will be strong match for both clubs.
Both teams have a dominant way of playing. Barcelona can be more favored, but I'm just worried about their defenders who I think are not very strong this season. There are still gaps even though in some matches it was closed by Barcelona's ability to dominate ball possession. But facing a strong opponent like Munich is clearly a tough test for Barcelona. It will not be easy to win the match. Before the match against Munich, Barca must face Sevilla who cannot be underestimated. Likewise, the match after facing Munich, Barca will face Madrid. They must be able to maintain their confidence.
If you look at the game play of Barcelona this season you will realize that they are not confidence of themselves when you compare them to the Barcelona of before let's not being up the matches they have won in the domestic league their performance against Monaco clearly explained a lot of tension and weakness in their team which shows that a little shake in the team can affect their entire performance even when they are dominating the game.
Playing against a Bayern Munich team that is not very solid like before Barcelona will need to be extra careful because they may not have the opportunity to dominate the game in possession as they used to do when they have the stars in the team so Bayern Munich will have the advantage of attacking Barcelona since it is obvious that their defense is not solid enough this season.
Barcelona may be looking at securing a draw against Bayern Munich but if Barcelona plays against Sevilla they should be able to win the game because Sevilla doesn't have a good record this season in the league but Barcelona against Real Madrid I don't know if they can defeat Real Madrid since Madrid confidence is also shaking.