Munoz has to make full use of his length to win this fight. As Gradovich moves forward, he should look to take a half step back and time a sweeping lead hook as the Russian presses into range.
When Gradovich is in front of him, Munoz should cover quickly, then counter instantly with the lead hook or straight right.
Munoz has to be ready to throw punches as soon as there is a pause in Gradovich's attack. Whenever Munoz is attacking, he needs to remember that Gradovich is going to attack him as soon as he is done.
Gradovich is aggressive, but patient. He has excellent balance, and the wilder Munoz gets with his own attacks, the worse Gradovich will make him pay.
So Munoz needs to keep his composure. If he is feeling overly pressured by Gradovich, he needs to retreat slightly, not lunge forward with an attack.
If he backs up behind a jab or lead hook, he can be fairly confident that Gradovich will be moving into range for it.
This isn't exactly the way I have seen Munoz fight in the videos I've watched of him. But this is a world title opportunity, and I think he needs to make some adjustments to get over the hump here.