I took a steroid before my tennis match
Did you really? Why would you take steroids?
Because I was desperate, my opponent is really good.
You should not take drugs to enhance your performance artificially. You are cheating yourself because you are not really winning plus drugs are not healthy.
I want to win so I choose to take drugs.
But do you really win if you take steroids? That's just cheating, and you should win the honest way.