In the first section of Beowulf, which part is the most clearly the rising action?

If you study the first part, it seems like when Beowulf faces Grendel and in their fight Grendel loses one of his arms, this part is most clearly the rising action as the rest of the story actually carries the effect of this early fight. It is also the most exciting given the condition that Grendel’s mother is such a powerful entity who surely will be ready for the revenge.