O'Neill said: "The key to winning is that we must stay cool. I am not saying that will be easy in such a passionate atmosphere but that is what we must aim for.
"They are intense affairs but I think the discipline becomes so important because if you can keep a reasonably cool head, then you will definitely have a better chance.
"If you do that you can keep a clearer head. But I am saying that and I should be taking the same advice.
"Hopefully, I can keep a clear head otherwise it will get animated on the touchline, for the want of a better word.
"The discipline aspect is very important - very important indeed particularly in derby games. I thought last season we might lose a player and the usual suspects might come to mind. You wouldn't expect Sessegnon to be sent off the pitch."