Henry Maske vs Virgil Hill II comes to kind. Maske lost the first fight and hadn't fought in a decade but ended up winning the fight. Both were way past their best but still.
Watson, Benn and Collins all completely changing tactics v Chris Eubank while going in betting underdogs
Pep vs Saddler is virtually a miracle win. I don't know what the odds were for LaMotta to beat Robinson, but I can't imagine they were in Jake's favour! Charles vs Marshall may be one, but the only reason Charles lost so bad the first time is because he was badly injured, so I don't know if this one counts.
Ossie Ocasio-Jimmy Young II. Young comes in a flabby 220 for a tuneup on the undercard of Holmes-Norton expected to cruise past the unknown, awkward Puerto Rican and get a shot at the winner of the title fight. It’s pretty much in the bag. Only Jaws outworks him and out-awkwards Young to win a split decision. Fast-forward seven months later and Young has dropped six pounds and looks to be in much better shape and Ocasio wins comfortably in the rematch. He fights Holmes and gets jabbed to death while Young is relegated pretty much to the heavyweight scrap heap.
Word games. Physically he wasn't as big as Jake when Jake beat him, he was giving away 20+lb. It's more than putting Leonard in with Hagler in 1980, with Leonard making 147 and Marvin weighing 160 - Leonard'd be obliterated.
I hear what you are saying, i wasn't being funny with my reply, i was just replying in response to the thread question. But yeah, Benn, if he didn't get that point deducted, and Watson, what a damn shame, he won the first in my opinion and was well on his way to not only beating Eubank, he was humiliating him as well with the beating he gave him.