Just before the halftime whistle, there was a controversial decision by Turkish ref Cuneyt Çakir that could have shifted the tide in favor of Bayern München, as Marcelo apparently got away with that seemed to be a handball inside Los Blancos' box.
The Brazilian left back tried to block a cross by Joshua Kimmich, but while doing so, the ball hit his hand. The only clear shot shows Marcelo entering the box, which means Die Roten should have been awarded a penalty.
Marcelo jumps to block Kimmich's cross...
Have a closer look at that play.