Board Thread:Theories and Speculation/@comment-26388300-20160325102110/@comment-734582-20160414104157

Naruto's instincts went rusty, not his actual powers. Kurama berated him for not paying attention, as with his godlike sensing he should've been aware that Shin marked the sword, or he should've seen the sword coming. But he tanked that sword (which also cut Madara in half) and then went on like it's nothing.

There's nothing to suggest that Sasuke is stronger. The whole manga theme has always been that they're roughly equal.