Sasuke would never beat pain.
*their eyes are linked*
1 pain absorbs jutsu, its impossible to hit them physically *unless* you have *mastered* frog kumite like naruto has. Frog kumite takes the energy around you and hits your opponent where you wouldve wanted, even if they dodge it.
The other pain(the girl 1) can do massive summons to call dogs, birds, etc.. 1 can revive...do i need to continue?
Sasuke would never be able to beat pain. He would go through his chakra to fast and wouldnt be able to lay a single finger on either pain. He's to damn stupid, and hot headed to be able to do what naruto has achieved.