Naruto isn't a CQC expert and that small not serious skirmish is nothing to brag about. If anything that would take away from Itachis CQC ability considering Sage mode Naruto>>>>KCM naruto by a long shot and ninjas like Deva fought Sage mode and didnt get off'd, 3rd raikage and Muu were easily dodging and reacting to KCM naruto. Instead of looking at it as "itachi kept up with KCM Naruto" you should instead see it as KCM wasn't bested by itachi. Since KCM only gets a faster Shunshin (Not CQC upgrade) and more chakra tricks. His skills did not get better nor did his striking speed get faster.Lol forgot about summons. But Itachi can just cancel it out, then Manda would probably turn on Sasuke. CM2 durability is only strong in the wings. Every other part of his body isn't that durable thus Itachi easily penetrates with a Kunai. Chidori Nagashi would briefly stun him, but then a crow clone feint or something of that nature stops/lets him evade Sasuke's incoming "finisher" and then the match continues.
They never did, but:
-Itachi was matching KCM Naruto.
-Evaded a blindside attack from B.
-Played with B in the speed area.
-Countered his 7 swords dance far better than MS Sasuke did.
-Was reacting/moving just as fast, if not faster, than Early EMS Sasuke.
That is all enough to warrant Sasuke getting whooped by Itachi in a raw CQC encounter.
Next dodging a blind side hit from a Big ass sword is nothing to talk about. Itachi when he was a kid did blind tactics for fun. Bee wasn't "blitz'ing" any one and they all were talking.
Bee with the big ass sword not once was overwhelmed by Itachi, so again it isn't anything to brag about especially when neither party was serious.
Itachi Did exactly what sasuke did at first. Only thing different was he retreated instead of trying to combat it knowing it was a losing battle. The fact that "the great Itachi" didnt counter attack and find openings showed he was out classed and smart enough to regroup.
Sasuke with EMS didnt get better in CQC/Taijutsu so he would never (except older version) be better then Itachi with just EMS in that area. More chakra does not make your body move better or faster in CQC with out proper training. Unless a scan is shown to prove more chakra made Sasuke better in CQC it's fan fic at it's best.