In what fight would a losing boxer be able to 100% defeat his opponent at the peak of his career?

Prime Mike wouldn't have beaten prime Lewis anyway

 

Ali beats Holmes is the first one I can think of.

Prime Wlad beats both AJ and Fury.

 

Prime Manny certainly beats Horn and Ugas.

Prime RJJ beats Danny Green.

SRL beats Camacho and Norris.

Prime Holyfield beats a heap of guys who beat him.

There are hundreds of these situations.

 

Ezzard Charles at his absolute best would have beaten the daylights out of any one of the guys he lost to post Marciano.

 

There's also Ali-Holmes.

 

Carlos Zarate would definitely have beaten Daniel Zaragoza in his prime.

Prime Larry Holmes beats Evander Holyfield

 

Duran vs Paz and Camacho prime to prime, Duran claps both.

 

Joe Louis and Ezz wipe the floor with Marciano.

 

I'm assuming you don't want the obvious ones, there would be too many to name.

I think Louis beats Marciano

Wlad beats AJ

 

Tyson vs McBride would have been a better example.

 

There must be 1000s so I've tried to keep it to title fights rather than fights where the better fighter is becoming an opponent and only used ones where us Brits have been the beneficiaries.

Pedroza v McGuigan
Curry v Honeyghan
Stracey v Napoles

 

(he actually beat them but was robbed)

 

1085 Don Curry beats 1986 Honeyghan.
1986 Honeyghan beats 1989 Starling
1986 Mugabi beats 1991 Norris
1981 Tony Sibson beats 1988 Frank Tate