The final ended 21-21 after 60 minutes of regular play before Barcelona edged ahead in the additional periods to lift the trophy.
For the fourth straight year, the championship match went into overtime. After the first 10 minutes of extra time also ended level, the game extended to a rare second overtime, making it an 80-minute battle.
Barcelona sealed the win in dramatic fashion as Aleix Gomez Abello scored the decisive goal in the closing seconds, while goalkeeper Emil Nielsen made several crucial saves to keep them in contention.
The tournament ran from September 26 to October 2 and featured nine clubs from six confederations, including teams from Egypt, Germany and the United States.