May be open to doubt? Why would anybody take that claim seriously?
I suspect that either Cortes or Pizarro, as military men who had served in hand-to-hand combat (although armed with swords), would have easily beat Atahualpa, who I don’t think would have ever engaged in real physical combat himself. I’m not sure whether Moctezuma would have participated in combat himself, but I don’t think he would have been able to beat the Spaniards. Aztec combat was more ceremonial than down-and-dirty; the Spaniards would have been more like street fighters.
Cortes and Pizarro, however, were never heads of state, unless you regard them as being de facto rulers as viceroys.
I was going to mention Amin, who was his country’s light heavyweight boxing champion. Hand-to-hand, no weapons, I’d take him over any 20th or 21st century leader.
Not Teddy or Putin. Roosevelt was a very good judo/jiujitsu student in the era where judo was just starting to emerge from jiujitsu. In addition to his boxing training and all-around cussedness, I have no doubt that he would own Amin.
That said, Putin is still a class above Roosevelt. Teddy was a very good fighter for a politician; Putin, in his prime, was a very good fighter for a fighter.
Barehanded, my money is on Peter the Great of Russia- he was a huge (6 foot 8), strong guy.
Oh! Yeah. Kamehameha is certainly going to make it to the final rounds.
Also, FDR in Battle Mode.
I’ve a sneaking suspicion that Putin would really enjoy going mano-a-mano with Alexander the Great, I reckon he’d even let the young Macedonian be on top for a while but eventually he’d pull him off.
Then a quick warm-down, shower and relaxing message.
Whatever Putin is paying his PR team, he should double it. Those guys are doing a real good job.
Yeah, good call.
Leonidas and the other Spartan Kings would get DQ’d when they disregarded our unmanly modern Pankration rules disallowing groin strikes, rabbit punches, 12-6 elbows, finger breaking, etc. … 
Why would Putin beat Netanyahu? Netanyahu was in Sayeret Matkal, which practices Krav maga. You’d assume an elite special forces operative trained in a deadly hand to hand combat art would beat a KGB operative trained in Judo. Krav Maga, unlike Judo, is designed to work in a real world fight ASAP so you can move onto other issues. Judo is a competitive sport, not a method of winning a fight as fast as possible.
As far as historical figures like the king of sparta, those people also existed in a time when healthcare was non-existent and malnutrition was rampant. So any modern competitor could be more physically hardy than someone who was plagued by injuries and malnutrition.
Harald Hardrada, 7 foot tall berserker King of Norway.
He sounds hard to top in a hand-to-hand fight.
Crazy Horse or Sitting Bull could whoop some ass.
I’d pay to see Vlad Putin go hand on hand with Vlad the Impaler (also known as Dracula.)
Lincoln…he was a lanky 6’4" street fighter who grew up strong doing backbreaking physical labor. He would have wiped the floor with Putin.
Probably because of the number of seriously badass things he was able to accomplish.
Another Russian for your consideration; Tsar Alexander III, not as tall as Lincoln (6’2") but he was noted for his physical strength.
The Vikings also have to have a look in - I nominate King of Norway Harald Hardrada, another who was noted for his height. During his exile in his earlier life he was in the Varangian Guards, the Byzantine Empire’s hard as nails mercenaries. He must have also been in pretty good shape enjoying swimming and rowing.
Amin was 6’ 4" - according to google, he had six inches in height on Teddy, and nine on Putin. Yeah, yeah, elite martial arts skills. Assuming both sides are at least minimally competent fighters, I’ll take the height and reach. (Which is also why I don’t think I’d take Amin over the seven-foot-tall berserker viking.)
Not so much with the malnutrition if you’re the king. It’s good to be the king.
Amin is a good addition to the discussion. Amin would be a tough opponent in boxing, but if the fight is MMA rules as per the op his skill set might be limited. James Toney had a championship boxing career with an 74-8-5 record (45 by knockout), but when he tried to make the switch to MMA Randy Couture defeated him fairly quickly by simply not boxing him - Couture shot for his legs, had him on the ground in 25 seconds and submitted him in a minute or two. If Amin can’t expand his skill set to at least staying off of the ground, he might be in trouble (if he doesn’t get DQ’d for trying to eat his opponent first).