Sasuke was a rookie with MS. he had used it only 3 times and had aquired new jutsus each time. but nothing proves Sasuke was less skilled or tactical. Sasuke proved to be better using Amaterasu than Itachi could. and Sasuke has proved to be very tactical multiple times in his fight with Itachi, Deidara, Danzo etc.
and thats another thing Itachi is as tactical as Konohamaru.. come on get real. what has Itachi done thats has people say he's soo smart and tactical? he is a genious yes but that in context means he was a prodigy child. but in combat he always showed to just be stronger than his opponents, not show tactical. true tacticians have been revealed when the tactician outsmarted his oponent. Naruto, Kakashi, Shikamaru of course, Minato, even Jiraiya. but not Itachi. only thing tactical he did was plant Amaterasu in Sasuke to kill Madara. remind me again how exactly did that turn out?