I would follow Chuteboxe's prediction, and put money on a points decision or possible late round TKO (round 9 onwards) for Oscar. The Mayorga of today is not the Mayorga that battered Six Heads and Forrest, the beating Trinidad gave him is the type that ruins a fighter.
If you want to go for a real long shot, I would put a little money on Judah stopping Mayweather. It's highly unlikely to happen, but not entirely implausible.