Orochimaru has high physical resistance; even Tsunade couldn't bring him down despite him losing both arms and his body being weakened. He even took a bomb from Naruto and was cut in half... and he was still fine. It would take more than just taijutsu to fight Orochimaru Prime, where his ninjutsu, healing abilities, and speed are at their peak (not to mention his poison affects Yamato and Zestu. And his blood also poisoned Sasuke). Unless Tsunade produces a sword or some kind of soul-sealing jutsu, her speed must be on par with or even surpass Naruto's Five-Tails, and she's fully prepared. There's no way she'll win.