Watch Marcelo poke the ball into the back of his own net.
It looked like this had been coming in the build-up to the goal. Croatia had a couple of very effective counter-attacks and Ivica Olic nearly scored just a couple of minutes before this. On this occasion, Olic was the provider, playing the cross that led to the own goal.
Croatia were always going to be a tough opponent for the Brazilians because of their midfield. At the moment, Ivan Rakitic and Luka Modric are winning the battle in the center and Brazil don't seem to know what to do about it.
It's also worth noting that Brazil aren't used to this situation. They didn't trail at any point of the 2013 Confederations Cup.