Topspin is the name of today's game. By adjusting the amount of spin, this versatile stroke can be used defensively, setting up the ball for an aggressive opportunity--and then to finish the point with an outright winner.
However, there are occasions when the use of underspin is necessary, and every player should have a full arsenal of shots where the racket meets the ball with an open face.
There is really a family of underspin shots starting with volleys.
A good addition to your game would be a chop shot. This stroke is played by cocking the racket head above the wrist and punch down very sharply from the elbow.
The stroke will give a low skidding shot to the opponent giving you breathing space if you were on the defense, or you can improve your position in anticipation of a weak return from your opponent.