Kuchiki Byakuya vs Uchiha Itachi
Itachi starts with 3-tomoe Sharingan activated and Byakuya starts with Shikai. They can go Mangekyou and Bankai whenever they want.
Rules:
100 yard starting distance.
Both in their primes.
Itachi can see Byakuya and is able to hit him. Therefore, no reiatsu crush allowed.
Restriction on Tsukuyomi, Izanagi, Izanami, and Kotoamatsukami.
Who would win?