It all depends on which Moorer showed up.
If Moorer decided to slug it out, he would play into Mercer's hands & would endure a very difficult night, as going toe to toe with Mercer is not a good idea unless you are truly confident in your ability to take punishment, however If Moorer elected to box, he would win a unanimous decision, as Mercer's stamina was not the greatest & he'd probably get tired chasing Moorer.