Are you dumb :| So you think Naruto didn't have to train to reach his current level. Smh, Sasuke knows he's inferior so why don't you know?
Hmm Naruto just has to ask Kurama for power and Naruto just gets it easy, just check part 1 just asking is all it takes.
Narutos kyuubi chakra mixed with his chakra and the huge chakra helped him get Sage Mode. Naruto would be dead the day he was born if it wasn't for Minato sealing Kurama.
True Orochimaru stated that Kurama chakra was fusing with Naruto, Sage Mode requires huge chakra something that Kurama gives the user.
I'm sure Kurama made it harder for him to gain Sage Mode.
Kurama made it impossible to fuse with the frogs, I really doubt Kurama made affected Sage Mode training in anyway.
Because he was exhausted after using Kyuubis chakra and even not tried to fight anyway.
Maybe Naruto was exhausted there no denying that, Naruto didn't fully recover from the 4 tails transformation. But there is prove Sasuke was stronger here is the prove
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and here is the quote in page "
And with were we're at right now, we aren't strong enough to bring Sasuke Back... He gotten way too strong." If you know the Viz version that is even better, I don't like relying on fan translation since there could be errors.