Atletico made a mistake because they thought they would get full points after their second goal, so from this side Barcelona took advantage. This was indeed history for Barcelona, making a memorable comeback, from 2 - 0 to 2 - 4, something that rarely happens in big matches.
Leading by two goals is not a lot to be pursued by any team that has more strength like Barcelona and I am actually not too surprised by the number of goals. But I am more surprised at the very close time of the goal that Barcelona was able to make so that from a losing position to winning. Now Atletico Madrid already knows that facing Barcelona must be in a much more serious mode this season if they want to win the match.