How did Sumbu Kalambay get knocked out by Nunn like that?

Just mw, can't think of anyone taking out the top dog in a round.

 

Very few big fights with those stipulations have ended in KO1 at any weight.Kalambay vs Nunn was to decide the top dog though, keep that in mind.It doesn't really qualify.

Moore getting mangled by Leonard Morrow is one of the most notable of those results for a great fighter, even though ole Mongoose wouldn't win the title for a few years, he was post-Charles losses and very close to being the best at the weight.

 

It was simply a case of "Things happen." Kalambay got caught flush on the chin, and out he went. It just happened. Kalambay rarely if ever got caught flush like that, and when he did, he usually shook it off. Nunn wasn't a big hitter, but he just happened to land right on the button. It happens.

 

Kalambay wasn't any undisputed champion but I think he was the number 1 going into the fight.

I wouldn't really class spinks v tyson as a qualifier because despite spinks being the ring/lineal champ he weren't no number 1.