You're welcome, and here's how I would do it:
1. I let them throw the first punch (that way I can call it self-defence).
2. I dodge that first punch, grab and twist their arm, then break their elbow over my shoulder
3. I shove them and twist the broken arm
4. I grab the back of their head and slam their nose into my knee
5. I do the same to their stomach and crotch
6. I grab them by their waist and make them do a dolphin dive into the concrete, dirt, whatever we're standing on at the time
The damage:
Broken, twisted elbow
Broken nose
You can bet that they won't pick a fight with you again. :)