Bayern Munich contributed in its own downfall as defensive errors led to all of Porto's goals in the UEFA Champions League defeat.
Porto took advantage of a host of defensive errors to stun Bayern Munich and prevailed 3-1 in their UEFA Champions League quarterfinal first leg.
Bayern, the winner in 2013, came into Wednesday's clash at the Estadio do Dragao as the favorite, but a trio of mistakes at the back leaves the German club with it all to do at the Allianz Arena next week.
In a dramatic start to proceedings, Ricardo Quaresma took full advantage of two glaring errors from Bayern in the opening 10 minutes, first converting from the penalty spot after Jackson Martinez had dispossessed Xabi Alonso and then been taken down by Manuel Neuer inside the box.