Giratina is a tough pokemon, but we’ve seen what heppens when he tried to fight Arceus. Arceus is just far too powerful and can block techniques from all elements! Giratina is powerful, but I’m not sure he’ll be able to break the barriers in time to take down Arceus. (Even if he did Arceus has the speed advantage) Arceus wins.

Fanfic version below

https://dreager1.com/2012/12/15/tournament-smashers-episode-23-giratina-vs-arceus/