I am mostly worried by Del Potro. I don't think that Tiem, Wawrinka or Tsitsipas can beat him in Bo5. As far as serving machines are concerned, anything can happen. If there serves are on, and Rafa's return is off, he may repeat Federer's Wimbledon.Nadal has Thiem, Anderson, del Potro, Tsitsipas (sorry but I think he's awesome), Isner, Wawrinka
Federer has Cilic, Zverev, Djokovic, Kyrgios??,
Are we all so certain it's going to be a cake walk for Rafa?
Federer's half looks more dangerous IMHO. The first three are definitely a problem. Kyrgios doesn't belong to this company.