There are lots of possibilities given Sasuke's list of abilities
We've already seen what adult sasuke can do and nothing combat wise has changed
but the specifics aren't important
They are. Fact is naruto's asura mode matched sasuke with all the bijuu and he can still do it.
Fights are not just about the raw power of each combatant
There last fight with each other was
was that the Asuras had more sheer power (high chakra reserves, vitality, etc) while the Indras had greater skill and the special eyes
Yet Hashirama was more powerful than Madara which is why he captured Kurama to use against him and he still lost in the end. Those two were close in power sure, but they weren't equal.