Last sunday night, I was watching live exhibition match played in NY with newer players playing with wood racquet and older ones with the new racqets. Sampras played with wood Vs Lendl. When I saw Bryan brothers playing with Wood racquets Vs Jensen bothers, I was thinking in my head: "They can't be serious, Why are they doing this? Tomorrow they need to play US Open. Won't playing with tiny, heavy wood racquets throw their game off when they play with their regular racquet tomorrow?" Sure enough, I read news they were ousted first round. Why do players at the top do these kind of mistakes when Grand Slam title it at stake?