During the chunnin exams sasuke was really weak than gaara and naruto, after sasuke got his cursed level 2 he was still a little weak than naruto, that is as someone has already mentioned that naruto didnt summon the boss frog and all... he must be holding back, the final blow was the resengan vs chidori... while seeing the elements, resengan is wind, chidori is thunder, wind vs thunder, if both resengan and chidori was in a matched level, which one will win ? ofcourse (resengan) wind will win, so i say that naruto was holding back at that time, after sasuke starts and finished training with orochimaru, naruto with jiraiya, sakura with tsunade (old granny, heh) gaara became the hokage and every one has got a lot more stronger... now if u ask which one, gaara, or sasuke will win, nobody knows who will, but i think that sasuke will win since he was able to beat orochimaru, and i remember a quote, in naruto shippuden, the sand granny (the one who fakes death) says if u go 1 on 1 against the sharingan, there is no possibility to win. to fight a sharingan, atleast 2 people are needed so that if one of them gets caught in a genjutsu, the other one will release him/her from it, so this is what i think