Man...Jiri was rocked badly by Rakic in rd 1 in his last fight and was almost finished. Jiri is tough as hell and is live, but he's also reckless at times and Poatan's power isn't in question. And unlike other guys he generates a ton of power with no windup, he's a special striker. Watch how short the punches are that wrecked Strickland, there are VERY few guy on earth capable of that.
Again, Jiri can win and if he mixes grappling and keeps Perreira guessing he can land big shots like you said and definitely find a finish of his own. But he's in danger every second in that cage that Alex isn't on his back.