you know what i advise?
dont back down, just walk right throwgh him and land the hardest shots you can in his nose and his eyes. hes not gooa see to well after that pummeling. it doesn matter if you get hit, hes probabely a cock and punches like a girl anyways. if you really really hurts somone, they dont want to be an idiot and plough throwugh you again.
this is a potentially hazerdous plan of attack and the other suggestions are probs better...but if you find they dont work, then punch him so hard he ends up in another time zone!