Call a spade a spade: Naruto and Obito defeated Kaguya.

[DarkStar1]

Naruto used ingenuity, wit, presence of mind, skill, trickery, and his raw power to take her down while Obito protected him from the gravity bone strike and aided in Sasuke's retrieval to help him. Sasuke played little to no part in the big picture in this fight.

Naruto went toe to toe with her with the chakra arm exchange and tanked her blow
Naruto forced her to retreat with Kage Bunshin and fooled her with Gudo Dama handoff.
Naruto (needlessly) stalled for time so Sasuke could help with the seal.
Naruto ate her alive with Kariki Musou and then tore her arm off with a blitz
Naruto's Bijuu Rasen-Shuriken Barrage was the nail in the coffin and caused this metamorphosis as BZ explained.

Sasuke's Susano'o was destroyed multiple times, he was BFR'd twice, and he did not land 1 solid hit on her. His S/T jutsu failed as well, and his support wasn't even there for 90% of the fight. This was the Naruto and Obito show, and now Kakashi is joining the crew.

Only thing Sasuke is needed for at this point is the mark on his hand.

 

[sage1999]

we all said kakashi is gonna fail. He didnt. We all sayng sasuke gonna fail. The truth will come out soon brother

 

[AllHailKurama]

This is true lol I gotta say, Naruto is dominating Kaguya, seemingly on his own.

 

[DarkStar1]

we all said kakashi is gonna fail. He didnt. We all sayng sasuke gonna fail. The truth will come out soon brother

I'm not saying Sasuke will fail, just that his role was completely negligible in this fight. He could have not been there and not much would have changed. At all.

 

[Indora]

Is tge fight already over, because you said Naruto took her down. Did madara come back or jashin or the ramen guy?

 

[Sound]

Well Obito just helped bring back Sasuke and saved Naruto. Gave Kakashi his powers so we'll have to see for now.
He didn't directly affect Kaguya.

Naruto affected the battlefield more. Sasuke is needed for the seal.

 

[Liquid Snake]

It's crazy how sasuke is so useless and now kakashi has PS and kamui so maybe he can fill the void sasuke isn't filling

 

[cafe123]

Naruto soloed her pretty much, the only thing he lacks was ability to seal her permanently.

 

[Cassus]

Maybe the sage should have given both powers to Naruto instead of giving the yin power to Sasuke.

 

[TRE MERCER]

Obito and Naruto wins. Senju dna plus Naruto's chakra means DMS Obito is basically Edo in terms of chakra. Naruto has already proven he can blitz Kaguya. Obito can follow her through dimensions. They flood her dimensions with Naruto clones and she eventually gets overwhelmed.