In Reality Sasuke's stamina is even Less than Itachi's.
See Itachi vs Sasuke fight Sasuke was only using Normal Sharingan with Some small power jutsu while a Sick Itachi was using MS then Susanoo n amaterasu still both Sasuke and he lost all the stamina at the end of the fight. So imagine if Sasuke had Susanoo n amaterasu he could have lost his stamina even before Itachi did. Itachi was ill n weak in that state still he used such OP jutsu. Even though itachi's only weakness is his low stamina this fight Shows Itachi's stamina is still much more than Sasuke's.
NOW Remember his fight against Deidara ?
Deidara is one of the weakest of 9 akatsuki members still Sasuke lost all his stamina at the end of the fight even when he used manda's life to save his own life.
NOW WATCH OUT RECENT FIGHTS SHOWS SASUKE LAST MUCH LONGER IN FIGHT BUT THATS NOT BECAUSE HIS STAMINA WAS HIGHER, THE FACT IS UZUMAKI STAMINA IS BEAST LEVEL, HOW ?
Before Killer Bee fight every time Sasuke was out of stamina without even showing much fight but in the fight against bee Sasuke got Help from KARIN to increase his chakra. If it wasnt for the UZUMAKI clan's chakra, sasuke was dead in 2 min fight.
Not Only that against the fight with 5 Kages. KARIN helped his too many times or else sasuke was Out of stamina soon.
Plus against Danzo Karim actually played more than a 35% part to help sasuke to win.
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Sasuke dont have Big stamina, the Only thing helping him to get More stamina is KARIN. It shows Uzumaki stamina is beast level.
Thats fact.