Difficult to define what the best match means, let alone choose one. I'd put them in two categories: one for the most representative Pep football at its best, which is the type of football I enjoy the most, and the other one for the most pleasurable matches to watch in general.
Best representation of Pep football:
Bayern 5-1 Arsenal 2015 Total domination of the game, hopelessly helpless opponent
Roma 1-7 Bayern 2014 Same as the Arsenal game
Dortmund 0-3 Bayern 2013 Götze brought on for the second half and absolutely changed everything. This is the distant past where Götze was meant to be our Messi...
Bayern 4-1 Mainz 2013 Same as the Dortmund game
The most enjoyable matches:
Dortmund 0-2 Bayern 2014 (Pokal) Legendary Javi Martinez performance
Bayern 4-2 Juventus 2016 Need I say more?
Bayern 6-1 Porto 2015 Again, need I say more?
Madrid 1-0 Bayern 2014 I know this is weird, but I thought we played amazing that match and was very unlucky not to score. Then I thought the second leg will be piss easy and then....
The matches against Atletico will be included after 2 weeks from now