Chelsea are in a very good form at the moment. If Chelsea face Barcelona or Bayern Munich then maybe the match will be a very strong match for Chelsea. But I think Chelsea will win. Chelsea are in a very good form at the moment. Every player of Chelsea is in a very good form. Although Barcelona or Bayern Munich are playing very well. But it is not possible to say for sure what will happen or not. Because both teams are very good and strong. And it is never possible to say when what will happen on the field of play.
As it currently stands about the performance of the teams you mentioned(Chelsea, Barca, and Bayern Munich), they are all in good form, from the front line to the defense line. No lapses in the squad depth. It will be hard for any of them to grab the 3 points of the match, if not much effort and tactics are put in the game to consider winning.
For winning, they got to play with all their might or expect a loss match which none of them, I believe would like to lose their match no matter who's the host or away team
It is not possible to put any of these teams ahead to win. Because if you consider the team strength and strategy, then Barcelona would be ahead, but the reason for concern is that Chelsea will definitely take advantage of their home field and try to do something good against Barcelona. The big reason for concern for Chelsea is the victory of Bayern Munich and Napoli. Chelsea will have to face a lot of big tests in the away matches against these two top teams of the Bundesliga and Serie A League and I expect these matches to not bring positive results for Chelsea. Here, the possibility of Chelsea losing is high. Because both teams were the top teams in their domestic leagues last season.