Conditions: Sasuke has the KM Cloak and the Curse Mark
Knowledge: Manga for Hashirama, Full for Sasuke
Distance: 20 Meters
Battlefield: Grassy Plain
Restrictions: Sage Mode
I'd wait to see more from Sasuke, like a giant Susano'o, or giant Amaterasu before I say he wins. With full knowledge though, this will not be a cakewalk for Hashi.