no......
if a person with a kunai connected at the same time as a person with rasengan, then it doesnt matter which is stronger.....
edit: correction, it doesnt matter unless the person has crazy healing like naruto or kabuto. But regardless, a direct blow to the heart, naruto's source of kyubi chakra, can still knock him out of it

and apparently 2nd lvl seal isnt < demon chakra if naruto failed to do anything whatsoever against sasuke in that form