I had a feeling Rublev had no chance against Zverev. Yes, Zverev has no reason to go out before SF in USO, unless he finds a way to beat himself again which he does often in slams when it matters.
Rublev is interesting. He's sort of in the same group as Zverev, Medvedev, Tsitsipas, etc., but he's a bit behind. They're all taller, for one thing. It will be interesting to see how all of these guys managed each other, going forward, as it does make sense that we're talking real potential rivalries.
As to Zverev and the USO. He is positioning himself well, and he's playing great tennis. If he doesn't have a quality finish at this USO, or even a win, we will wonder about his head. Same with Medvedev. Of course Novak is the favorite, but these guys have to get off the fence and fight for it.