There's no rules when you're fighting like that, my father taught me how to box when I was young, and I have no problem saying I fight dirty as hell. You should have either poked that guy in the eye, or kicked him as hard as you could in the balls to incapacitate him. And while it might look "douchey" taking off your shirt makes it much harder for someone to grab a hold of you.
I avoid fights though, but if it comes down to it, your eyes will be poked, liver and kidney punches will be delivered, and I will be stepping on your feet before I throw a punch, if there's sand anywhere in the vicinity it's ending up in your eyes too.