Bayern defeat Barcelona at the Camp Nou in a match that saw the Catalans record 5 shots and none on target.
The Spanish giants are without Leo Messi and it was a new life for them under Koeman.
Barcelona is trying to revive its lost glory and this game was one that would show their intent.
However, it was Bayern Munich that opened the scoring in the 34th minute with Muller.
Thirteen months ago, Bayern destroyed Barcelona by scoring 8 goals against them.
It seems the Calatans have not gotten past that shock as they were a shadow of themselves with no identity.
Many Barcelona fans have criticised this team under Koeman as they are finding it hard to get results.
Although with the addition of Aguero, Depay, Garcia and Luuk de Jong, the team is yet to find balance.
It might take a while before they shake off the exit of Leo Messi who is arguably their best player ever.
Polish forward, Lewandowski doubled the lead for Bayern in the 56th minute of the game.
New boss and former Leipzig manager, Julian Nagelsmann started life on a very good note.
Bayern are now unbeaten in 19 away European games.
Many expect a tight game but would not be shocked to see Bayern defeat Barcelona.