The pros use some measure of sidespin on groundstrokes quite a bit. The banana shot is an extreme example of this. Check the link above for a great view on how Roddick executes the banana shot.
Quite often, elite players will hit a bit to the "outside" of the ball rather the directly on the back of the ball when hitting topspin or slice groundies. This will cause a bit of bending to the left or the right as the ball flies thru the air. Once in a while, they will hit a bit on the "inside" part of the ball to get the ball to spin the other way to get the ball flight to flare out a bit (like on some inside-out shots).
Hitting on the outside of the ball is probably used more than hitting on the outside, particularly true for FH shots. This practice is often employed when hitting x-court topspin shots (either FH or BH), especially for short sharp angles. It is also very useful when returning an incoming x-court shot DTL. When attempting a DTL shot for a ball that is coming from a x-court direction, the ball will tend to go wide unless the player hits a bit on the outside of the ball -- to get the ball to curve in a little bit (away from the side line).
For BH slices, players will sometimes hit the inside of the ball to get the ball to curve one way or they will hit the outside of the ball to get it to fly straighter or to have it curve the other way.
Another type of (horizontal-axis)
spin, spiral spin
, is often used in conjunction with (vertical-axis)
sidespin. Spiral spin does not cause any left-right deviation in the flight of the ball, but it does cause the ball to veer to the left or the right when it bounces (note that regular sidespin does not
do this). This spiral spin is the type of spin that causes the ball to bounce in the opposite direction on a twist serve.