Casper Ruud has his detractors, but nobody doubts his clay-court prowess. Ruud is a different animal on the dirt, where he consistently makes deep runs and has twice been a Roland Garros runner-up.

The US Open, the final major of the year, is here. On the men’s side, Novak Djokovic is the defending champion. Fresh off winning Olympic gold for the first time, Djokovic will be looking to win a ...