With the whole 6C base upgrade for Nasuverse, I guess matches like these can be done now, maybe (as opposed as Pokémon matches.....rip). Probably gonna end horribly, but here I go. Two waifus wielding grand looking Island busting swords.
Fate Saber is used. Tohka is in her normal Spirit form. Speed equalized. Battle takes place in Fuyuki City with both sides 10 meters apart.
Win via SBA. (Inb4 I do Shinou Vs Shidou or something similar next)