If defense is still Bayern Munich's weak point, Kompany will definitely make improvements when facing Barcelona in the Champions League after the international break is over.
Barcelona is indeed in the best condition but Barcelona's victory so far is because the teams they have defeated are overall still below Bayern Munich's quality.
Visiting Barcelona's headquarters, I still don't think Bayern Munich can have high-level difficulties like the lower teams in the domestic league.
It was that mistake of defenders that cost them Aston Villa entry to win them in their last match but I see the same mistakes again in their last domestic leagues with Frankfurt, they went goal for goal which is very poor for the team. The forward and midfield communication is very great but the defenders are very poor in making quick stiffness against there opponents, if Lewandowski and Lamal has such opportunities, they are going to squeeze Bayern Munich.
The two also looks desperate, they both has lose a match and has dropped them from the top of the table and will want to win this match. If Bayern improve on defending, they might end the match as draw but if they don't, Barcelona are going to print goals on their head but I expect goals from both teams, no way Bayern will let them go and Barcelona will do some harm too them.