Arrow? I don't recall Itachi having that feat!?Itachi wins very high difficulty, but Sasori is a very bad matchup for Itachi. Being a puppet, most of Itachi's MS techniques won't have any effect of Sasori. Unlike Sakura, Sasori has lots of long range jutsu, which will prolong this fight.
Once Itachi finds out Sasori's weakness, Susanoo arrow to the chest. If Itachi can't figure out Sasori's weakness, he will lose because of low stamina