Your first reaction is almost always to correct the on the ball defender. Then you want to correct the rotation of your other four defensive players because you know your defensive system isn't designed to allow straight-line drives to the basket in a half court situation.
We all know that your players will be quicker and stronger when they are in a proper defensive stance. Watch your players when the guard the ball, and players usually do a decent job of getting themselves in a good stance.
|On the ball stance.|
|Players off the ball standing straight up = slower rotations.|
One idea to help improve this situation is to have one of your assistant coaches be in charge of watching the defensive stances off the ball. Your players should know that an assistant is in charge of this. Now the expectations have been set and the players know they are being held accountable for it. This can also be done in film sessions with your team. Point out the players in a good stance off the ball and the players that are not. Show examples of good defensive rotations that all started because a player or players were in a ready position. If your four defenders off the ball are in a ready position the chances of a straight line drive by an offensive player with the ball decrease because your players are quicker to rotate to stop the ball.
Sometimes the corrections needed to be made are the fundamentals of the game...and these corrections can make the biggest difference.