I'm not sure about who'd win, but you can bet if I wasn't laying between the two waiting to be trodden on, I'd be found behind the one who appeared to be loosing! Big yummy body-mashing butts and bone breaking paws!
I like this piece, but something about Slim's right hand stands out as odd, I'm not sure what it is. It's either the lighter tendons, or his little finger which looks broken o_x; owch!
Take a gander at "Drawing Dynamic Hands" by Burne Hogarth. It's been recommended to me before, and while it's too advanced for me, it did look choc'a'block full of drawing goodness for those strong neck-snappin hands!
Hmm I think Makuyama has a slight edge having a sumo wrestling background & all. Plus he's a heel right? He can go for the mask. Slim would be distracted trying to keep it on & would give Makuyama an opening.