Itachi definitively won.
He had a debilitating terminal illness that inhibited his battle skills, while a perfectly healthy Sasuke couldn't even push him to his limit (ie., Obito clarified that Itachi pulled a facade pertinent to the scenes that felt like the latter was forcing him to his limits.), which implies just how much stronger Itachi was, in stark contrast to his Kyødai ━ Sasuke.
Itachi was extremely resourceful like exemplified by him perfectly calculating even the climax with remarkable accuracy, and even forced Sasuke to emaciate his chakra reserves ━ the irony in this, being that, Itachi is the one supposed to possess substantially diminished reserves of chakra ━ and yet, he's the one outplaying his Kyødai in a battle of attrition, which is just ridiculous outright to say the least.
