Barca defeated Sevilla 2-1 in Morocco, with Ter Stegen stopping Wissam Ben Yedder's late penalty to secure the triumph.
He said at the final whistle: "I do not know if it was even a penalty.
"You cannot throw yourself down like that. I'm happy that we could win this title.
"It is very important to win these trophies, we are a team that knows how to do it, we are very happy for today's victory."