I’ve actually wrote this one let me know if anyone disagrees Jack Dempsey vs Jack Johnson An aggressive come forward puncher vs a defensive counter punching boxer. A great mix that would provide an entertaining fight while it lasted. Johnson would start well landing some good counters and tying up Dempsey when up close. While Johnson has his opponent tied up he fires some hard uppercuts that hit the target while Dempsey was crouching. However Johnon mistimes an uppercut and with Dempsey’s now free left he unloads a cracking hook that hits Johnson square on the chin. A further 3-4 punch combination sends Johnson down for the count. The Galveston Giant is back on his feet but for the following two rounds is fighting on the back foot. With his low punch output and lack of power the Manassa Mauler is just gaining in confidence. By round 7 Dempsey has worked over his opponents face and body with Johnson sporting a closed left eye and some heavily bruised ribs. Jack Dempsey comes on strong and manages to land some crisp shots that put his foe back down to the canvas this time the ref’s seen enough and waves the fight off. Verdict – TKO win to Dempsey round 7
I read an interesting piece that I found online that basically suggests part of the reason Johnson was as dominant as he was is partly due to the size advantage he had over many of his opponents. That would not be the case with Dempsey. Additionally, Johnson never fought a "swarmer" type of fighter with potent KO power at any time. Ultimately, I think a prime Dempsey wins a TKO within 10 rounds.
Johnson did hold size advantages in some, but by no means all of, his key fights. He beat Sam McVea x 3, and was outweighed in each one, by 25lbs, 16lbs and 17lbs respectively. He beat the 6ft 3.5ins Sandy Ferguson x 4, in the one fight where their weights are recorded, Johnson was outweighed by 30lbs. Jack beat Denver Ed Martin twice, in the one fight where their weights were recorded, the 6ft 3.5ins Martin was 23lbs heavier. Jeffries was 19lbs heavier when he fought Johnson. Yes, Jeffries was a good 10-15lbs heavier than at his peak, but so was Johnson. Battling Jim Johnson outweighed Jack by 9lbs when they fought. Again, by then, Jack was heavier than he had been at his best. Jim Johnson averaged c.225lbs during his career, whereas I think Jack Johnson was around 190lbs at his best. There are other Johnson opponents who were less notable, such as the 6ft 4ins Jim Jeffords, who were bigger than him, too. I see nothing remarkable in the split between opponents that Jack Johnson was bigger than, relative to those he was smaller than.
Frustrating fight for Dempsey…temporarily. KO in 7. Johnson’s general ring craft & tie ups will cause problems, & he hit hard enough to get Dempsey’s respect, but the speed of Dempsey’s assault will tell.
I’d pick Dempsey under the modern ruleset, but the fight becomes 50-50 if it’s under the 1910s ruleset. Johnson is almost certainly capable of controlling, and ragdolling Dempsey around in the clinch. He’s also a slightly better infighter as well, although Dempsey’s power and formidable infighting himself might put Johnson‘a lights out in a fight where he’s behind.