awesome matchup. When I think about this it is very hard to figure. I would think that David Tua would land the left hook and rock Mercer into a defensive fight and win a decision. I do not think he would knock out Mercer, but he would hit him so hard it would change momentum for Mercer. Mercer had a good chin but Tua is a good puncher who would probably hit Mercer, if not on the chin close enough to get Mercer to back off.