It's either going to be Casper Ruud or Andrey Rublev. They play against each other and the winner will move to the semifinals to face most likely Daniil Medvedev. It's not a very enticing proposition going against the Russian but it's a place in the semifinal and you can expect both of them to fight for it hard. It's been a solid event for both but in this matchup, Rublev should have the advantage.
They played five times so far with Rublev winning all of those matches comfortably. Even on clay, Ruud's preferred surface the Russian was dominant so he should have the advantage as well. However, he will need to play much better than against Djokovic.
In the 2nd one, Cameron Norrie will have a chance to take on Novak Djokovic. They never played before and speaking to ATP recently, Norrie admitted that facing Djokovic is like a nightmare. Whether it will truly be a nightmare remains to be seen but the 21:00 CET should be an interesting one for the crowd who will certainly enjoy it.
14:00 Rublev A. (Rus) - Ruud C. (Nor)
21:00 Djokovic N. (Srb) - Norrie C. (Gbr)