If I recall correctly, Itachi slayed his entire clan and his parents while using a sword right? We also saw this when he killed his parents in front of Sasuke. Not only that, Itachi effectively disarmed Kabuto and landed a strike on kabuto with the sword when sasuke couldnt hit Kabuto even when the sword was covered in lightning. To me, Itachis mastery of the sharingan along with his tsukoymi could easily overwhelm so many people.