Is the competition on clay stronger than grass or vive versa? I shall compare players on clay with players on grass using an objective and data-driven method.
Method: I compared the best performance of players at Roland Garros (RG) and Wimblebon (WB), and used the ATP ranking as a tie-breaker in case two players are tied.
Objective and data-driven ranking:
Thiem on clay (1 F, 2 SF at RG) >>> Cilic on grass (1 F, 0 SF at WB)
Schwartzmann on clay (1 QF at RG, #11 in the world) >>>> Kyrgios on grass (1 QF at WB, #21 in the world).
Zverev on clay (1 QF at RG) >>>>> Zverev on grass (0 QF at WB).
Djokovic on clay (1 RG title) <<<< Djokovic on grass (3 WB titles).
Del Potro on clay (2 SF at RG) >>>> Del Potro on grass (1 SF at WB).
Goffin on clay (1 QF at RG, #9 in the world) >>>>> Müller on grass (1 QF at WB, #60 in the world).
Results: Competition on clay is clearly stronger than competition on grass. It seems like Federer is not dominant on grass anymore, and their fans need to think of new excuses.