#2 Positivity always pays off
When you have won 15 of your last 16 matches and haven't conceded a goal in over 14 hours and are leading your league, after being close to the relegation zone at the start of the season, no matter who you are playing, you don't start the game by playing like an underdog. Not only that, you don't also go ultra-defensive and trying to play for a 0-0 at home.
While it is true that Bayern have a slew of world-class performers, replete with precision, pace and panache, they also had a midfielder in central defense and had to play David Alaba and Philipp Lahm, two players who usually play in midfield, in defence. With all that in mind, Juventus' first half performance couldn't have been a more polar opposite of the way they should have approached the game.
After going 2-0 down, however, they decided to finally go forward and attack. In the end, that was the difference between being out of the tie at 2-0 to still having a glimmer of hope at 2-2. That should serve as enough proof to Allegri that if the opponent has a weakness, one should attack it and that positivity always pays off.