Sasuke havd NEVER lose to Naruto.NEVER!!!
He never flat out won until the beginning of Shippuden either. At the valley of the end, Naruto chose to scratch Sasuke's headband instead of potentially killing him via stabbing. Sasuke however, wanted to kill Naruto. It was a tie since Naruto could have inflicted as much Damage to Sasuke as he did to him.
The only time Sasuke outclassed Naruto (completely for the duration of a fight) was at the start of shippuden. Even then, Naruto had the option of using Kurama's power to fight him, but he chose not to. It's not an unfair advantage either since Sasuke's curse mark is Orochimaru's chakra. Naruto just had the better helper. Naruto would have killed Sasuke if he let Kurama loose like he did with Orochimaru.
As for the summit. That wasn't even a fight. Just glorified dialog.
Naruto has never flat out lost to Sasuke without the choice that he could beat him. In other words, Sasuke being ahead of Naruto is plot.
Also, your thread is completely wrong about how a fight between them would go! You have the premise that Naruto has relied on Kurama's intelligence rather than his own for the series, and when he can't rely on his intelligence, he'll make fatal mistakes.
First off, where is shown that Naruto
EVER relied on Kurama for intelligence before the fight against Obito? You'll find none. Naruto's accomplishments in jutsu and strategy wise are his own. He's not going to be any less intelligent against the fight against Sasuke.
On top of this, Kurama can no longer be suppressed. When Sasuke did what he did, Naruto didn't want Kurama, and if anything, helped him. Kurama was also acting as a separate being. Now, they combine their chakra. Sasuke would have to "suppress" Naruto. That's impossible for perfect jinchuriki. Itachi, Obito, and Madara all have had the occasion to suppress a perfect jinchuriki, none of them did. If you say Sasuke's better at genjutsu than Itachi, you have a problem. Sasuke can't possibly have a special ability that all those Uchiha don't.
You saying Naruto would loose due to screw ups is like me saying that Sasuke would loose due to his ego making him underestimate Naruto and gets stomped as the result. Naruto is above Sasuke right now, it's not even a question.