I would add one thing to the advice in this excellent article: Expect the unexpected. Put another way, allow youself a way out! The last time I encountered such a situation was when a GT40 I was setting up to pass did a snap spin directly in front of me. I was looking at him eye to eye. It was the first time I ever locked up the brakes on the GT40.
Got off of them quickly and drove around the spinning car. It's always best to avoid collecting another car. Going off offcourse is second worse. Going bye under control is best , but staying alert to the unexpected is key.