"It will be a killa and a thrilla and a chilla, when I get that gorilla in Manila." This was the biggest grudge match of all time - Muhammad Ali v Jo Frazier. It was their 3rd contest having previously won one each. And it went all the way with Ali winning as Frazier's corner through in the towel before the start of the 15th round. Ali admitted later that he had put everything into the 14th and had nothing left in the tank - they had fought to a standstill but with Ali still able to claim he was the greatest.
Relive it : https://www.youtube.com/watch?v=1R6WSAJGS5A
Also available as a Print