I'd be kinda surprised. Whether Sasuke seems to have the upper hand or not, for him to beat Naruto again and having Naruto never beat Sasuke in a shinobi fight would throw me for a loop. The MC couldn't beat his rival, ever? I'd laugh Lol But if that was to happen, I imagine Sasuke spares Naruto and actually comes to his senses about doing things alone and him and Naruto decide to try and find peace together along with the SA and current Kages.