system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How can a tennis player dominate so consistently over competition on a certain surface: Sampras/Federer on grass, Nadal on clay, etc. ???
gpt
Clay is really slow and so you get longer rallies and so you need to be incredibly fit. Nadal is one of the fittest tennis players in the game.

Grass is really fast so it's all about accuracy to place the ball out of reach and/or big serves. Sampras probably had the best serve ever and Federer is probably the most accurate tennis player there has ever been (Federer's even better indoors where there's no wind and so he can place the ball to within millimetres).

Hard court is somewhere in between.