Barcelona rested Lionel Messi, Neymar and Luis Suarez and almost paid with an embarrassing defeat against the third-tier minnows.
Daniel Mainz gave Hercules a shock second-half lead but starlet Carlos Alena spared Barca’s blushes with a fierce 25-yard strike.
Messi, Neymar and Suarez were given the night off ahead of Saturday’s El Clasico against Real Madrid at the Nou Camp.
Daniel Mainz gave Hercules a shock second-half lead against mighty Barcelona
Luis Enrique’s side struggled in the first-half as Paco Alcacer had their only meninglful effort on goal with a free kick that was well saved by Hercules goalkeeper Ivan Buiges.
Hercules grew in confidence as the game went on and flashed a warning with a header that went just past the post.
Daniel Arraiz gave the Segunda B side a shock lead in the 52nd minute when he bundled the ball home at the back post.