Mei High-Diff.
60 Metres means Itachi will have Trouble closing in for CQc.
Once she puts up her Mist I doubt Itachi will have enough Energy to activate Susano and use Totsuka.
Even if he does she can easily adjust the mist's Ph levels to her will and Pressure him with Suuton just enough to exhaust him.
Mei has shown the ability to Spew large Volumes of Yoton which could help her with the outlasting Process.
Amaterasu requires Concentration and he only has 2 Shots I doubt with the Mist active he can Use Black Flames.
The only way he can get a Amaterasu on Mei is if he activates Susanoo Use Totsuka to blow away the Mist and then Fire Amaterasu at her. Up this will just kill him in the process.
Healthy or Edo take this but Not Normal Itachi.