Why the slice does more work on grass than on any other surface

Two effects that compound

A ball struck with backspin arrives at the court with rotation that resists the bounce, so it emerges lower and slower than a flat ball would. On a surface that already produces a low skidding bounce, those two effects combine rather than cancel, and the resulting ball stays very close to the ground. The opponent must then strike from a contact point below his knees, where the racquet cannot be swung down through the ball at all.

His only option is to lift, which means hitting upwards and losing the ability to generate pace without also generating height. That is the entire mechanism, and it explains why the same shot is far less effective on a high-bouncing surface where the ball recovers its height.

The slice as a controlling shot

Because the reply must be lifted, the player who sliced knows roughly what is coming back and can begin moving forward before it arrives. This converts a shot usually described as defensive into one that sets up an attack, provided it is hit deep enough to prevent an aggressive reply. A short slice does the opposite, offering the opponent a ball he can move onto and strike from a comfortable height inside the baseline.

Depth is therefore the variable that determines whether the shot controls the point or hands it over, and it is harder to judge than it looks. The margin is small because a slice travels slowly and a small error in racquet angle produces a large error in length.

Using it on the backhand side

The one-handed backhand slice is the natural expression of this, and it is one reason the shot has survived on grass while declining elsewhere. It allows a player to change the height and pace of an exchange without the preparation time a topspin backhand requires. Two-handed players slice less often and use it primarily on stretched balls, which means their version arrives short more frequently.

The technical requirement is the same either way: a high take-back, a downward and forward racquet path, and a stable face through contact. Players who chop at the ball with a steep path generate backspin and no depth, which is the failure that gives the shot its defensive reputation.

Approaching behind it

The slice travels slowly, which gives the player who hit it time to move forward, and that time is not available behind a driven ball. This is why the approach shot on grass is so often sliced, even by players who almost never use the shot on other surfaces. Arriving at the net behind a low ball is also safer, since the opponent lifting from below the knees cannot easily hit a passing shot with pace.

The lob becomes his better option, which is why net players on grass position themselves slightly further back than the geometry alone would suggest. The exchange is a well-defined one and both players usually know exactly what the other is trying to do.

Returning serve with it

Against a fast serve there is often no time to prepare a full swing, and a blocked slice return is the shot that fits the available time. It also keeps the return low, which denies the server the waist-high ball he wants for his first shot after the serve. That is a substantial tactical gain from what looks like a purely defensive response to being overpowered.

The technique requires the racquet to be set early and the contact to be made in front, since a slice hit late floats and sits up. Returners who master it can neutralise a serve they cannot attack, which on grass is frequently the realistic ambition.