You cant compare the two, Boxing is more of an art. UFC fighters just swing wild allot of times and get cough or catch the opponent with a lucky shot, ie look at Silvia nd Arlovsky, arlovsky was clearly winning and bam one lucky shot, why because he had no defence like a boxer would have. either that or they roll around in the ground and see who can catch the opponent in and arm bar or something. So it could go either way , standing up the boxer would win hands down, but on the ground it depends if the boxer also knows how to wrestle.