Context is important here. One of the times Kattar looked so good in the championship rounds was against Zabit, a fighter who for all his talent falls off badly in long fights. And I think Ige was just outmatched in more ways than one -- not that he's a bad fighter by any means, I think Kattar was simply the better man in there and a bad stylistic match-up for him.
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Max's three losses in five-round fights have been as follows:
- A loss at Dustin Poirier in which he fought at 155 lbs. It's generally agreed that he was "bloated" (as @taugrim alluded to) and didn't execute the build-up to Lightweight in an optimal manner. Even if he had, Dustin has some of the best cardio at Lightweight himself and would have been have been easily capable of matching him in a five-round war. Max managed to take 1-2 rounds off him all the same, depending on who you ask. His output remained relatively steady, but he of course got his bell rung by the bigger, more powerful boxer across five rounds. Again, I would argue that his cardio and ability to fight five rounds at 145 isn't a problem IMO.
- A loss to Volkanovski -- a well-conditioned fighter in his own right who came prepared to execute a gameplan and has excellent cardio of his own. This is a convincing loss and no argument to be made here. He let the shit get kicked out of his legs. I don't know why there was ever any controversy about this defeat, no immediate rematch was needed IMO despite what his deluded fan club might say. However, for what it's worth Holloway's output never really faded -- cardio was not his issue here.
- A second (split decision) loss to Volkanovski that is still argued about to this day. That being said, most would agree that Volk came on stronger in the championship rounds, so I'll give you that -- but again, Alexander is a really well-conditioned fighter in his own right and Max was hardly gassing late or anything. I just think he chose to start sooner than he usually does.
Point of order -- Max has actually gone five rounds on the regional scene prior to coming to the UFC before, but I know you were probably talking about his time in the Octagon only. And the Ortega bout (in which Max threw a blistering amount of significant strikes) made it well into the championship rounds, for what that's worth.
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Anyways, I'm not trying to trump up Max's resume or shit on Calvin Kattar by implying that he has no cardio. He might very well go out there and be able to stand with Max for all five rounds and maintain a respectable pace. That'd be great -- as someone who'll be rooting for him, I really hope he does. But I can't help but value Max's experience, chin, cardio, and heart -- all of which have been proven in five-round fights against a higher-level of competition than that which Calvin Kattar has faced. Fingers are crossed for Kattar to get the upset, though.