Tsunade regen's from every piercing attack Hidan has.
The circle is broken by a simple ground pound.
It depends on the situation. Intel or no Intel?
Without Intel: Tsunade doesn't have byakugo activated after a simple scratch. She has no idea about the circle and Hidan stabs himself game over.
With Intel: Tsunade has byakugo activated so she will recover from his attacks, BUT Hidan also now has intel so he will stab right through his head on the get go, or constantly stab himself to the point where it is irrecoverable. Smashing the ground will disrupt the circle but amidst the rubble Hidan can easily create another one, he can take advantage of the dust and rubble blinding Tsunade. With intel Tsunade might be able to pull this off if she tags him with body pathway, then its game over for Hidan, but that's the thing she will have to tag him, while he knows full well what she is capable of so he will try to avoid being hit which he is capable of.
Either way he can win in both scenarios.
You choose.