There have been a lot of times where going into the 12th round of a fight, I knew one of the fighters definitely needed a KO. But I am not usually on the edge of my seat because it seems like a final round comeback KO never really happens. For example, I wasn't very worried that Postol would stop Crawford in round 12.
Green K for any good examples of this actually happening, except for Chavez/Taylor. No K for close calls like Chavez Jr/Martinez or KOs outside of the 12th round like Glowacki/Huck.
not really a comeback per se but shane mosley- ricardo mayroga was a very close fight going into the 12th round (shane was ahead by SD). when he finally dropped mayorga in the final round and then finished him off right at the bell.
Great finish by shane, and great effort from mayorga for making it a tough fight.
There was a ten round fight that mickey bey was winning the whole time till john molina jr knocked him out in the last round behind like a mofo on all scorecards
Best comeback I ever seen was not a 12 Round, I recall a fight in which John Tate was winning a fight by ease by winning all 14 rounds against Mike Weaver than out of no where Weaver lands a left Hook that drops Big John Tate like a sack of Potatoes winning by 15 round KO
Audley Harrison v Sprott II was a good one.
Not exactly a high level fight but Harrison was fighting one handed, he could hardly move his right arm and was down on the cards and staggered in the 12th. Then Harrison unleashes a beautiful left hand that absolutely stretches Sprott.
Brilliant domestic level scrap anyway.