Did Kimbo's opponent cheat? Check it out, you can clearly see something in his fists. I've played the clip frame by frame and whatever it is, is doesn't fall out of his hand when he opens it. At one point you can see him remove this object from his right hand just before he goes to shake Kimbo's hand. Not long after Kimbo slaps his hand, he puts the object back into his hand.
I've always assumed that if someone had something inside their hand in a fight it was meant to pack a harder punch. Maybe somebody with image enhancement skills can get a good shot of this object and work with it to see what it is.