All in their own way but this is what came to mind in no order.

Tex Cobb - Larry Holmes
Diego Corrales - Jose Luis Castillo II
Du Ku Kim - Ray Mancini (had this fight not had that horrible horrible ending and aftermath it would be considered one of the best fights of all time)
Billy Conn - Joe Louis
Jeff Lacy - Joe Calzaghe
Vazquez - Marquez I,II & III
Henry Cooper - Muhammad Ali
Vitali Klitschko - Lennox Lewis
Alexis Arguello - Aaron Pryor
Ron Lyle - George Foreman
Julian Letterlough - Julio Gonzalez
Mark Breland - Aaron Davis