Imo, Greb beats the one-dimensional Tua handily. Harry got the better of Dempsey in sparring, not fazed by Jack's fearsome left hook. Harry would emphatically out work and outpoint Tua. Not even close!
Interesting point, it's just a bit of a leap of faith to think Greb could take such hard shots for 12 or 15 against Tua or Dempsey, even if he can avoid being hit clean it's a big ask, though certainly not out of the question.
Greb chin isn't proven enough at HW to make such a strong claim. On the other hand, he beat solid hitting Brennan who wasn't small HW at all. Brennan wasn't on Tua's level in terms of power, but he was good fighter in his prime. So it's not impossible to see Greb beating Tua, but I wouldn't bet on it.
Ya'll can't be serious. After his last fight with Tunney, Greb said "He's getting too big and too strong for me to handle. I could lick him at one time but not anymore...." Gene Tunney was too big and strong for Greb, David Tua most likely stops him. You really want to try and swarm on TUA as a natural Light heavy? Tua is going to wreck his body.
In a longer scheduled fight at some point he would. If we are talking 3-4 rounds Grebs potential for avoiding a KO blow improves but certainly could occur at any second. Remember we are talking a middleweight and no middleweight is taking the power of either two of boxing’s biggest hitters.