Heavyweight boxing is a weird place with wierd men You have to have a golden chin or special recovery powers or insane skill to survive.
Hrgovic's chin is the one thing that won this fight. Can't see too many others in the HW division taking that kind of an onslaught for 10 rounds and staying on their feet.
They hit with so much force at heavyweight that having an iron chin is a lot rarer to find than can be found at lower weights where the conditions for it to thrive are better. The violent impact from the blows up there naturally results in that attribute going almost extinct but you do see them occasionally. Hrgovic does seem to have an ATG manidible up there with McCall or Vitali for example. It's how he just shows zero expression after taking a hell of a bomb, that's quite frightening.