Many believe this talented 19-year-old has unlimited potential, with effortless power on his serve and forehand, and an ultra-smooth two-handed backhand. But not all two-handers are alike.

This is the way to hold the racquet for the serve, volley, sliced backhand and smash. It is known as the chopper grip, because it is the way you would hold an axe. It allows you to swing the racket ...