Human Path wins due to 2 main reasons: chakra rods and lack of knowledge on Hidan's part.
At his best, Hidan is a physical match for injured pre War Arc Kakashi. At his worst, Shikamaru could react to his attacks. Human Path on the other hand, was able to react to Rasenshuriken and block hits from SM Jiraiya, so Hidan is not blitzing anyone here. With chakra rods, Human Path can fend off Hidan's scythe attacks much like how Kakashi did with smaller kunai, and he gains a massive advantage if he ever manages to pierce Hidan with one, as Nagato will then slow down/immobilize Hidan with his chakra, leaving him open to Soul Rip.
Lack of knowledge seriously hampers Hidan here as he will more likely try to make Human Path suffer first if he gets any of his blood before going in for the kill. This doesn't mean anything to Human Path seeing that it doesn't feel pain. Thus Human Path could take advantage (of Hidan's surprise at Human Path's lack of reaction to being stabbed in the legs) with a smoke bomb + chakra rod stab, then rip out his soul once he forces Hidan out of the circle.