The semi-finals will take place in Mexico at Saturday. Zverev against Thompson and Ruud against Tsitsipas. Zverev is the favourite in the first semi-final. But I would not underestimate Thompson, although he has had difficulties in his previous matches.
In the other semi-final there is no clear favourite. Both have won their previous matches, although Tsitsipas having a tie-break in the first set against Kovacevic. It is difficult to say who will win this semi-final between the two of them.
Zverev will clearly be the favorite in the semifinal match against Thompson and just look at how Zverev goes through every match with win, he is also tennis player who has managed to win 4 ATP tour singles titles.
We also know that Thompson is player who is persistent enough in every match to reach the semifinals now but he will not be able to beat Zverev.
Even though Thompson may can be able to face every difficulty in the future against Zverev, there is still no chance for him to win.
In contrast to Tsitsipas against Ruud, where it will seem more difficult to determine who will win and advance to the final, these two players have quite good playing quality.
They have also won various titles or awards in various competitions so we will see how the competition will be really fierce.
However, if I personally were in match between Tsitsipas and Ruud, I would be more inclined to make Ruud the favorite.
In the final match, if Zverev meets Ruud then we will see much more interesting match, and if this meeting really happens it could lead to sensational final match.