Never start the fight, but always FINISH it.
When my son was bullied and jumped by two kids in the boys bathroom, he defended himself and defeated both of them.
When called in to see the principal about the incident, she said it was school policy that he would be suspended for three days, and, she wanted to know what other punishment we would consider.
My response: well, he's going to the zoo with his grandmother on one day, and to an amusement park with me on another...because my son didn't start the fight, he simply did what anyone should do - he defended himself!
She was apoplectic! Could not understand - oh well - we went ahead and rewarded him for doing the RIGHT thing!
I love that story.
I hope your son had a great time at the zoo and the amusement park, because he did do the right thing.