Bayern Munich doesn't have strong defense and it is same with Barcelona but these two clubs have good attackers. However, I see Barcelona having advantage of Bayern in this match because they are playing in Nou Camp and Barcelona have sharp attackers and quality finisher than Bayern. Lewandowski have no choice than to play against his former team. It will be his pleasure to score against Bayern.
It is known that Bayern Munich are always winning Barcelona whenever they clash for quite some times now. But let's not use the past to judge the future because things have changed presently and there is no assurance that history will repeat itself again.
If we should judge based on Barcelona performance recently, I would say Barcelona are the favourites in this match, and aside from that, Barcelona will be playing at home, so definitely I think they should be favourites this time around.
Forget about their previous clash when Bayern Munich were winning them. I think this season Barcelona have also improved in performance, although I can't compare La Liga with the Champions League competition, but seriously, I will give Barcelona a higher chance of winning the match. So definitely they will do everything in their power to win the match, so obviously we can’t use their history to judge what will happen next in their match.