Spin is simply the direction the ball is spinning when it comes off the racquet. Spin can be manipulated by the path and angle of the racquet face at contact, and it allows a player to control the speed and trajectory of his shot, making it more accurate. Generally on groundstrokes there are two types of spin: topspin and backspin. Each is used for different tactical purposes during a point.

Topspin is generated by a low to high racquet path and usually accompanied by a slightly closed racquet face angle at contact. This causes the ball to arc over the net and drop into the court with a forward spin. It is the preferred spin used by most players because it allows them to hit deep, heavy groundstrokes while still keeping the ball in the court.

Backspin is achieved by a high to low racquet path that helps the racquet slice underneath the ball at contact. This produces a spin that causes the ball to travel through the air longer and skid upon the court resulting in a lower bounce for the opponent. It is often used on approach shots to force the opponent to hit up on the ball, or when a player is in trouble and needs to hit a shot that gives him more time to recover.

As a tactic, spin is used to change the pace and height of the ball during a point. By creating these changes, they allow a player to take control of the point and dictate what kind of ball he wants to receive from his opponent. For example, if two players are in a baseline rally exchanging hard, flat groundstrokes, and one player is looking for a short ball to attack the net, an ideal tactic would be to hit a high, hard topspin shot that forces his opponent to hit a short ball.

Likewise, if a player knows that his opponent is weak at the net, he can hit a short slice to draw his opponent in and make him cover the net.