A dirty little trick to slow down power players.
Okay, as a clay court specialist, I learned a lot of little things to drive the big flat hitters crazy. My coach, Lawson Duncan, taught me this one. He used it to beat Goran Ivanisevic 6-1, 6-1 at one of the big tournaments. I heard that Goran had a complete meltdown over this one too. Excellent way to slow the ball down.
Most tennis balls have tightly knit fuzz. Well, when they get wet (perspiration) and then are rubbed hard, they fluff out like crazy. They get huge and literally slow down incredibly. I used to take the ball when I was playing a big hitter or server and rub the ball on my forearms and forehead and then rub them really hard in my hands. They would get really big and totally slow down. They also would weigh more from the perspiration. This is great for topspin hitters as well as the strings can grab the ball better due to the fuzz sticking so far out. I can make a ball look absolutely crazy. It will also make your kick and slice serves have mega bite.