Boba Fett vs. Wat Tambor
Both of the combatants are from Boba Fett: A New Threat (approx. 31 months after AOTC). Boba has recently donned his father's Mandalorian armor and his weapons are basically the same as Jango's were. The fight takes place on Xagobah, at the top of Wat Tambor citadel, in the room they fought in in A New Threat.
So pretty much who would have won had Grievous and his guards not intervined?