Prince Oberyn is the rockstar of Westeros. He would be the man that the crowd worshipped. Oberyn isn't a huge back-street brawler, but he's quick, skilful and would prove to be a handful for more than a few top fighters. His feud with The Mountain would spell his downfall, though otherwise he could've gone all the way. Method Of Elimination: Oberyn's showmanship and lust for a confession would lead to a (literally) mind-blowing end after being taking too long in finishing off The Mountain once and for all.
9. Gregor 'The Mountain' Clegane
Gregor Clegane is a mighty man, if we're basing this on pure size and brute strength, there's simply no competition. Give him the belt and don't ask any questions. However, this is more than just a battle of brawn, you've got to have speed and brains in such a compact situation. He'd take a string of victims down with him, but The Mountain simply couldn't win the whole thing alone, with no allies at his side. Method Of Elimination: Oberyn would deliver big blows, but a man of The Mountain's size needs more effort to take down than the average human. Ultimately, the simple fact that The Mountain has made so many enemies would ensure that plenty of potential killers would line up for their shot at the big man with a variety of tools.