This may have been done before, but...
There would appear to be several ways a fighter can accumulate so many advantages before the actual fight, that he's got the proverbial deck stacked in his favor even before the opening bell.
1. Head games - What fights have occurred where one fighter has gotten so much into the other guy's head that it totally wins the first guy the fight. (One maddening example to me would be Fury-Wlad. Another was Mike Tyson vs Seldon, although you could probably put several Iron Mike fights here. I think Ricardo Mayorga tried real hard to use head games, but most of the time they didn't work out.)
2. Weight games - What fights have occurred where one fighter has totally drained the other fighter to the extent that the other guy comes in at less than 100%. Also, what fights have occurred where, despite the weigh-in attempts at a level playing field, one fighter enters the ring a full 20-30 pounds heavier than the other.... definitely not the intent of weigh-ins. Either that, or the guy shrunk himself, legally or not, to make weight and then ballooned by 20-30 pounds himself.
3. Judges games - What fights have occurred at a location or with appointed judges where it's practically guaranteed that fighter "X" will win, barring a knockout loss.
4. PED games - What fights have occurred where PEDs have pretty much decided the outcome of a fight, or at least made it 10 times more likely.
5. Rules games - My choice of ring size.... my choice of gloves... etc, etc. Any famous fights where this was a factor?
What other ways are there that fighters have sought an advantage before the fight that couldn't be overcome.