I was also looking at Rune after that upset win against Tsitsipas. But after that never heard from him. So he lost 7 matches in a row? There are some names in their, however, Peniston or Giron or Husler, he should have won that. Anyhow, let's see how he goes and hopefully he can get over that slump. Ivashka continuing his winning form in Atlanta, winning against Johnson of USA, and should be facing the top seed Opelka.
Also, an injured Zverev will be world no.1 by 15th of August unless Dani Medvedev reaches the final at Los Cabos (or) reaches quarterfinals at Canadian Open (or) semifinals at Los Cabos + at least 3rd Round at Canadian Open. This is all assuming Zverev himself doesn't play in Canada.