Important Roles of Non-Dominant Hand in Slice Backhand

Slice Backhand: Grip + Preparation

The use of non-dominant enables you to have a good shoulder coordination to slice the ball.
Use continental grip(Hammer Grip).

How To Develop A Knifelike Slice Backhand by TomAveryTennis

Tennis - slice backhand

Roger Federer - Slice Backhand Battle

There are seven basic shots in the game of tennis: the serve, forehand, backhand, volley, slice, smash and lob. Each shot is made by using a racquet to strike a ball with the intent to hit the ball over the net. Tennis shots are therefore named for when they are struck (in the case of the serve) or the manner in which they are struck.

Watch the Backhand Slice battle