FC Porto beat FC Bayern Munich 3-1 in the 2014/15 Champions League Quarter-Finals.
FC Porto’s 3rd goal was obtained after a major mistake by Dante, Bayern’s Brazilian Center-Back.
It’s more and more obvious the need to teach the Game, with respect to tactics, to footballers, from young ages onwards.
In this goal, Dante did not respect the Defensive Coverage Principle needed to be provided to Boateng, the other Center-Back.
Forward, being also the last defender positioned between the forward and the goal. Dante should have been closer to his team mate, in a diagonal, making himself the last defender, protecting Boateng’s back, hence providing him Defensive Coverage.
A few seconds later, Dante’s positioning is incorrect relative to Boateng, assuming he will win the air challenge. The arrow in the picture below points to the spot Dante should have been to cover for Boateng in case he was beaten.