Tennis doubles formations

The server's partner at the net is not a spectator waiting for a volley. Their presence removes the crosscourt return — the highest-margin shot available to the returner — because a crosscourt return has to pass them.

Poaching makes the threat real. The net player moves across to intercept a crosscourt return, and the server crosses behind them to cover the court they left. Even an unsuccessful poach is valuable: a returner who has seen one starts aiming closer to the line, and starts missing.

In the Australian formation, the server's partner stands on the SAME side of the court as the server rather than diagonally opposite. It removes the crosscourt return entirely, leaving only the down-the-line return — into a much narrower target.

It is used mainly against a returner with a strong crosscourt return, and it commits the server to covering the open side after the serve. That movement is the cost of the formation.

In the I-formation, the net player crouches near the centre service line, directly in front of the server, and moves to one side only as the serve is struck. The returner does not know which way they will go.

It denies information rather than space. Because the returner cannot choose a side in advance, they have to hit a safer, more central return — which is exactly the ball the serving team wants. The formation requires the server and net player to agree the direction before each point.

The strongest doubles position is both players at the net, where they cover the width of the court with almost no gaps and hit down on everything. The whole design of the serving formations is aimed at reaching it.

Both players back is the defensive position, used against a strong net team or after a successful lob. Its weakness is that it concedes the net, and in doubles conceding the net is conceding the point in most rallies.