However Jiri took the first round in their first fight. And it was Jiri first fight after year long pause and injury. He might havent "got in the flow" in that fight. Now he has tested himself against Rakic, he might be able to get the fight into full distance. Pereira has a left bomb, but Jiri was knocked out only one during almost last 10 years, and fought against strikers often. I think Jiri has a strong chin and have chances to survive bombs. Anyway, we will see it in few days. But I really doubt that he does not know about Pereiras left hand and would go whole fight with hand low.
Jiri only got that 1st round because of scoring a takedown when he managed to stay on the top, but didn't do much damage and Pereira escaped eventually. Before that, he was getting punished with powerful leg kicks.
That was a 5 round fight, so I wouldn't be putting too much weight on the 1st round. Usually fighters would just use it to "feel" their opponents etc.
And I think Pereira lacked a bit of confidence back then. That was his 2nd fight in the Light Heavyweight, he won his debut against Blachowicz, but it was unconvincing split decision and, before that, he got KO'ed by Adesanya.
So if we are to make predictions based on the first fight, Prochazka's best bet is to try to take it to the ground, but that's just not his style. And outstriking Alex will be hell of a task, but not impossible.