2) Hercules
Considering Barcelona’s fantastic treble in 2010/2011, Hercules might just be very aptly named after they inflicted one of the biggest upsets in history at the time.
Hercules had just been promoted to La Liga when they brought the Catalan giants to their knees at their very own home. Two well-taken strikes by Paraguayan Nelson Valdez and a glaring miss by David Trezeguet meant that Barcelona were fortunate to only lose 2-0 to their newly-promoted opponents.
While they paid them back for it in the reverse fixture, running out 3-0 winners, Hercules finished a very respectable 8th that season.
On top of that, they’ve given Barcelona headaches before. 19 years ago, they did the double over the Catalans, winning 2-1 at home and 3-2 away. With 3 wins from 4 games, Hercules are pretty much Barcelona’s antidote!
