The average serve speed for a professional tennis player is 148 mph. But many players are capable of serving a lot faster. Here's the fastest servers in the ATP tour. <br />1. John Isner (USA): 157.2 mph <br />2. Milos Raonic (CAN): 155.3 mph <br />3. Andy Roddick (USA): 155 mph <br />4. Roger Federer (SUI): 143 mph <br />5. Andy Murray (UK): 141 mph <br />6. Novak Djokovic (SER): 136 mph<br />7. Rafael Nadal (SPA): 135 mph
