Of endurance, yes. Not of strength.
What about the various moments where he has been shown to casually swing massive weights.
Uses giant boulders for exrecise.
Lifted a giant piece of building to throw at Daz.
The Davy back fight Groggy ring.
And so on.
Because plot required him too.
You see, Oda, unfortunately, does not treat injuries seriously. If you are not knocked out by them, they may as well be none-existant.
Case in point:
http://img1.wikia.nocookie.net/__cb20130724093228/onepiece/images/a/ac/Meigo_on_Whitebeard.png
And don't be like that, rapid recovery is one of the standarts of the manga. There are only two examples that didn't ended in working order within hours: Whitebeard and Ace. And that's only because plot required them to die.
You will notice, that until plot required them to die in a specific way, they were not hampered in any way.
And while things like Whitebeard getting to defeat most probable candidate for big bad of the series… in one blow... while having quarter of his head missing... are annoying to me, we can't argue that they are not a threat within the context of the series.
Zoro was able to move within minutes. Of course he could. This is Shonen Manga. At the same time however, the fight pushed him to the limits, and he was quite hurt. So yes, Daz was a threat, as far as the context of the series is concerned.
Again, I am not denying Mr 1 being a threat, I was pointing out my disdain to life threats which turn out to be nothing.
And before you say it, no I am not expecting the characters to die.
But When a character himself says how he is feeling like he's on Death's door, I would expect some kind of lasting effect on him.
I don't know, his fight against Hatchi showed how real Mihawk's attack was. He didn't die. And pretty much owned hatchi but it was still apparent that the injuries had an effect.
On arabasta though, he says "I am near Death's border" at one moment and "lol. no deep wounds" on the next.