I was also there and was just coming on here to post that I don't remember an invasion by supporters and I stayed until the end and after because I wait until the crowds going up the stairs from row A have gone!! I also don't remember anyone throwing anything on the pitch! Did anyone else see these invaders???
There was something thrown before Falcao took his penalty, DeBruyne threw it off the pitch. Haven't a clue what the invasion was and like you I was in my seat early and left after the bulk of the crowd.