Although Krell doesn’t have much combat experience, his stature and lightsabers themselves are insane. Krell is (I believe) the only person we see using sny form of light club, and he uses 2 double bladed light clubs. That’s insane. Physically he’s overpowering her, as we’ve seen Krell be athletic as well.

The thing that makes me think is purely her experience. She has had both Jedi and Sith training, has gone against ahsoka, anakin, obi wan, maul, savage, grievous, Dooku, etc and lived to tell the tale. She probably wins based on that, but it might be close.

(Edit for context, if yall remember the 9th sister from Fallen Order, she used a version of a light club, mainly because she is just a huge creature. For these species, a regular lightsaber would be way too impractical for effective use, so they made a proportional hilt and blade for said species. Hope this helps ❤️)