Glad you didn't get hurt, but don't get overconfident. You and your opponent are both relatively scrawny and inexperienced.
If being able to take care of yourself in a fight is important to you I suggest you try out Mixed Martial Arts as evo said. There are a lot of great benefits to learning martial arts.
For some, one of them is the self awareness and discipline to know what's worth fighting for. In my opinion, proving you're a big man isn't one of them. Suppose the guy decides to press charges? You have no chance of claiming self defense. You'd also be legally liable.
I'm just glad you kept it to fists..you don't want to be dealing with Use of Force. Trust me. I was required to take a two day course on what's acceptable and what's not and just about went to jail for hitting someone 6" taller than me and 40 lbs heavier with a swing-back elbow to the head while he was trying to stab me. I didn't have much room to work with.
The justification was that as a highly trained fighter my using a potentially lethal tethal technique on a single armed opponent was an "excessive" use of force. That experience was the only altercation I've been in since I was 14, I'm currently 20.
A lot of people might say that's crap, but after I had some time to think it through I realized something. Given the amount of training I had with blocking, slipping and dodging strikes and the fact that he (supposedly) had no fight training, my elbow was a much more deadly weapon than his relatively clumsily wielded knife. The fact that I used what's really a show-off move didn't help my case..and I think probably means that I was subsconsiously trying to be a big man by looking all "Ong-Bak" at the club (I don't normally go to those it was my good friend's birthday). It's definitely not something to be proud of.
Anyway, try to remember that this isn't the middle ages. Might is not right. I don't expect you to pay any attention to my preaching now, but be careful. Reality has a way of collecting its dues.
