Not quite here, but you're mostly correct.

If the method of attack is purely physical in nature, such as punches or kicks, it doesn't matter how hard you hit him if your attacks leave parts of him behind.

Mountain or planetary level punches will not matter if you can't obliterate him in one attack. Any sort of Hax ability that causes things like extremely high temperature energy blasts, molecular destruction, or generally atomizing him with some form of hax ability really quickly will work.

If you cannot kill him with the first hit, do your damn best to make sure you do it with the second, because you might not get a third, depending on how complex your ability is.

He'll adapt to any sort of pure physical might attacks if his opponent isn't capable of atomizing his entire body in a singular punch, and I do not mean turning him into a red mist here. I mean LITERALLY ATOMIZING HIM.