I think you have confused Volkanovski and Volkov 
If Volkanovski, a featherweight, would fight such heavyweight as Romanov, that would be hell of a show ~66-70kg vs 120kg
If Alex Volkov survive first round, Romanov would be without stamina till the end of the fight. Some people could say that Romanov, that has a wrestling base, would submit Volkov, that has a base of karate, I suggest you to re-watch Volkov vs Werdum fight. Werdum, as master of BJJ, did not manage to submit Alex during 16minutes. Tom Aspinall however managed to do that, but that is due to Volkov being slow. Volkov is tall, huge and slow.
If Volkanovski, a featherweight, would fight such heavyweight as Romanov, that would be hell of a show ~66-70kg vs 120kg If Alex Volkov survive first round, Romanov would be without stamina till the end of the fight. Some people could say that Romanov, that has a wrestling base, would submit Volkov, that has a base of karate, I suggest you to re-watch Volkov vs Werdum fight. Werdum, as master of BJJ, did not manage to submit Alex during 16minutes. Tom Aspinall however managed to do that, but that is due to Volkov being slow. Volkov is tall, huge and slow.
My bad, I got the names mixed up. I was visualizing one person and naming him the other. Probably that wouldn't have happened to me. If both of them did not have the same first name though -_-
Anyway, I actually think that Volkov being so tall is actually going to work against him. Because he is going against a fighter who is really good with takedowns. I am not going to say that it is easy taking down a huge tower of a man like that. But at the same time, it is easy to lose balance when you are so tall. At the same time, the power of Volkov is unmatched. He can one-punch knockout almost anyone.
So this fight is going to be an interesting one to watch.