And hand-eye coordination, and anticipation, and soft touch, foot speed, visual acuity, etc.

Roger Federer, who has yet to lose a set in this Australian Open, will play a quarterfinal against Tomas Berdych, whom he has beaten 19 times in 25 matches. ā€œItā€™s not so much fun,ā€ said Berdych the last time they played here.