The shoulders turn into the ball and the hitting arm/lever lifts to contact. Watch how the orientation of the racket changes. First the racket is pointed down to the ground at 45 degrees, with the butt of the racket pointed at the net. As Safin turns and lifts into the ball, the racket will meet the ball completely parallel to the ground.

On contact the racket meets the ball in line with the front foot, and the racket is completely parallel to the ground.