All i have seen so far is the same opinion from everyone. No Kakashi cannot beat Sasuke, nor Itachi. Who ever thinks that is retarded. Kakashi is a strong shinobe, but he isn't in the big leagues compare to Madara, Kages, Sasuke, Naruto, and Tobi. He is strong, but you all make his character depressing.
Kakashi is smart and he found a way to strike Tobi, which makes him smart.
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But just because he managed to hit Tobi it doesn't mean that he is above Itachi and Sasuke.
Itachi here found a quick solution to end Nagato's Celestial Terra Blast.
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It proves that he is calm in situations can make strategic battle plans in a jiffy, unlike Kakashi. He knew Tobi's abilities since the Itachi Pursuit Arc. He made a good plan because he knew his Kamui was related to his technique. So he gave it a shot and bingo he manages to hit Tobi.
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Sasuke shot two arrows at him, even if Kakashi warped them that doesn't make much sense to call him a victor against Sasuke. Danzo used his mokuton to block the arrow, if neither of them didn't have a way to block the jutsu. They both would of died against Sasuke's arrow. Plus, Sasuke knows Kakashi has Kamui, so he won't get careless if there was a next time.
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People forgot that Sasuke's Final Susanoo hasn't even been shown on battle. I imagine the power and it must be great to the tell you the truth. Kakashi can't take this down. Plus, he has own Magatama's coated in Amaterasu. How will Kakashi beat this?
Overall, Kakashi has improved, but that's it. Itachi can still defeat him and Sasuke will definitely defeat him. He is no match against either elite members of the Uchiha.