Rublev is a very close friend of Medvedev, so much so that he is even godfather of Medvedev's daughter. They know each other well as they essentially grew up on the ATP Tour together.
They practiced numerous times, and they played some pretty big matches both this year and before. It's a fascinating matchup between two players who essentially play a chess match on the court.
That's how it always is when you have two players that are familiar with each other. Medvedev is the better and more successful player, but Rublev has ways of beating him.
Rublev bested Medvedev in Turin last year so he can certainly do it again. When it comes to this year we saw two matches, and both were won by Medvedev comfortably. Medvedev also leads the H2H 6-2 which indicates a matchup problem for Rublev.
It truly is that way because you need incredible consistency from the baseline to beat Medvedev, and Rublev never really had it. He's gotten better over the years, which is why he beat Medvedev in Turin last year, but it's not a constant as this year's matches prove.
Overall I still think Medvedev will have the upper hand in the matchup because he's coming in very motivated after a few recent disappointments. Rublev hasn't proven that he can regularly tackle the Medvedev challenge, so I have my doubts.
I do expect a good battle and a close match but in the end, I do expect Medvedev to win, likely in two sets. He's just too solid overall for Rublev, who can be quite erratic and sometimes loses his mind. At the US Open this year, Rublev was up multiple times against Medvedev but never could see it through.
Prediction: Daniil Medvedev to win in two sets.