" And then, as I was bouncing the ball up and down on the grass, just about to wind up my body to serve, the umpire cut in. “Time violation: warning, Mr. Nadal.” I had apparently spent too long between points, gone over the legal limit of twenty seconds before I served—a rule that is enforced only rarely. But it’s a dangerous rule. Because once you’ve received that first warning, any subsequent violations lead to the deduction of points. My concentration had been put to the test. I could have made a scene. The crowd, I could tell, shared my indignation. But I knew, without having to give it a second thought, that to let my feelings show would do me no good. I’d risk losing that precious asset, my concentration. Besides, the momentum was with me and I was two points away from winning the second set. I put the umpire’s interruption immediately out of my mind and won the point with a terrific and, for me, very unusual shot. "

― Rafael Nadal , Rafa