Clay Liston 1 or Ali Foreman Take your pick. There's a reason he's one of two greatest heavyweights in history.
Spinks-Ali I Clay-Liston I Schmelling-Louis I Holyfield-Tyson I All of them were pretty big. Ali-Foreman was quite a sensation but not as big as the ones mentioned above in terms of an upset.
Could be Ali vs Spinks Frazier vs Foreman--Frazier wasn't a HUGE favorite, although he was 3-1. More of a huge upset in the manner Foreman man handled him. In fact, this is the answer i'm going with
Wow!!! Two great picks. I was stunned that Pacquaio was KOed , that Pacquaio lambasted Barerra and that Jones was put out with one shot in two round...I picked three, honestly. Trinidad - Hopkins Hopkins- Tarver
Clay-Liston in 1964. Look at the first round of Clay-Jones a year earlier, when Doug nearly floored young Cassius with a right hand which had him hanging on for dear life, then get knocked silly when flattened by Cooper's left hook in the match immediately preceding his shot at Liston. Review again his performances in those two bouts he had prior to challenging Sonny. He looked like a stiff breeze would blow him over if he got caught. Cooper and Jones were 180 pounders. Liston was over 30 pounds heavier than either, and it was unthinkable that his jab at least wouldn't reach Clay with consistency. Machen redeemed himself for his starching at Ingo's hands by reasserting his toughness with Liston. There was nothing yet to indicate Clay had that same quality of toughness and durability necessary to stand up to Sonny. Whitehurst had shown twice that sticking and moving could be a recipe for survival against Liston, but hardly a prescription for winning. Because of Hamas II [which has been on youtube], I don't think Schmeling-Louis II was that massive a shock. Yes, a huge upset, but Max also had an excellent trio of wins going in. Now, Braddock-Baer is one I don't buy because Maxie lost all the rounds against Carnera where a severely hobbled Primo kept his feet. Braddock was known to be a tough and punch resistant customer. If the Larruper failed to take him out... As for Ingo-Patterson I, Floyd had already been exposed as somewhat vulnerable by the knockdowns incurred against Rademacher and the light hitting Roy Harris. He looked good in taking out London, but Marciano considered Patterson to be something of a disappointment at this stage, not having acquired the requisite "ruggedness" against sterner opposition. [This after Rocky was stunned by how unexpectedly good Floyd had looked against Moore.] Patterson still didn't have any championship round experience, while Ingo had a pair of 13th round stoppages behind him. Johansson-Machen should have been a very serious warning to D'Amato, Patterson, and the American press and public, yet got dismissed by arrogant jingoism. But Ingo got to the EBU HW Title just before Patterson ascended against the Mongoose, and had arguably the better resume of wins behind him by the time they squared off. It's as if Clay had started juicing immediately after Cooper I, the radical contrast between June 1963 and February 1964. We wouldn't see a HW ATG improve that radically again from one match to the next until Holmes from Arrington to Shavers I. During one of his final televised interviews, Ali himself said Liston I was it for him, over Foreman. [Muhammad's speech was barely intelligible by this time, but he was in good humor, and sharp minded, making clear distinctions between Manila as his best fight, Liston I as his most important win, and Shavers as his hardest hitting opponent.] Again, when you look at Clay-Jones and Clay Cooper I from 1963, I don't know how it could be extrapolated by most that a new HW Champion was about to be crowned. Cassius didn't look any stronger than Patterson going into Miami Beach. Galento and a few others may have seen it coming, or they may simply have made lucky guesses.