2. At first, "tough one" was used in a derogatory manner. However, with the passing of time, the term has been used in a lighter, more colloquial usage
Feremy (the athlete): I know Coach. I think I could have gotten him. That was a tough one
Coach: You know, I'd highly encourage you to do a little more with the backhand. If you do, you can say goodbye to the tough ones.