Ok let's move on to Rome - Italian Masters.
Finally we are going to see Nadal here, and what a way to return that going up against Busta (US Open semi-finalist). But head to head, Nadal leads 5-0, no offense to his compatriot but this is Nadal's favourite court. And if he win, who's he gonna face next? Western & Southern Open finalist Milos Raonic. Not an easy draw for Nadal, but I think he can reach the finals again.
Both of them would cause Nadal a lot more problems on hard surface - especially Raonic. I don't know if Nadal is in good form or not but as long as he's got 1 leg and can still hold a racquet, he'll be my favorite on clay.
I'm guessing that Nadal is still in form, despite not playing in the US Open. And he has rested his body fully enough in this pandemic. And again, this is clay, his specialty.
Maybe a handicap on Busta would be a good bet, as you say, he's coming to Rome full of confidence and in top form.
Maybe Nadal woke up in the wrong side of the bed and Busta pulling an upset. who knows.