It occurred to me that it would benefit me to play without emotion - well, without emotion others could see, anyway. Card players profited from having a poker face so opponents wouldn't know how good or bad their hand was, and I figured a deadpan expression would work in tennis, too.

Players who win on a clay surface are those who can control the ball, playing steadily and accurately from the back-court, keeping the ball in play and moving it around with changes of speed and spin, and resisting the temptation to over-hit.

It can be a daunting prospect for any player to know that his opponent will never, ever quit.

Rod Laver Quotes