If you're talking Upset thats one things, but if your saying the greatest win as in the greatest Win on a boxers individual record. I'd probably have to go with Fraziers win over Ali
Louis vs. Schmeling I & II Jess Willard taking the title from Jack Johnson. Frazier and Norton beating Ali. Duran vs. Leonard I ...a handful of the very best right there.
In no order these are the first ten that came to my mind. I'm not counting wins with no footage like Greb vs Tunney 1 or Willie Pep vs Sandy Sandler 2. I'm also not counting non official wins like Whitaker vs Chavez or Harada vs Famechon 1. Ray Leonard vs Thomas Hearns 1 Juan Manuel Marquez vs Manny Pacquiao 4 Roberto Duran vs Ray leonard 1 Fighting Harada vs Eder Jofre 1 Fight of the century Rumble in the jungle. Ray Robinson vs Gene fullmer 2 Joe Louis vs Max schmeling 2 Benitez vs Cervantes Foreman vs Moorer. Remember this is not in any order.
Calzaghe had been a 3-1 on betting favourite with most odds-makers, Jones a 3-1 outsider. Calzaghe`s win v B-hop was far less convincing than his win over Jones. Calzaghe Odds On To Beat Hopkins - Eurosport - Eurosport.com
It's a toss up between Jake ''Money'' Paul defeating the sport of basketball in just his second pro (second ever fight) fight and Jake ''Money'' Paul defeating the sport of MMA in just his third fight.