Board Thread:Versus Debates/@comment-1018594-20150608074819/@comment-734582-20150611120942

AsianReaper wrote: @Ninwing That may be true. He did say something like he hadn't mastered the Sharingan yet, but during part 2 he was able to use his Mangekyou. In part 1, it already was a mangekyou. Maybe he was unaware it was a Mangekyou, and consumed more chakra than needed.

I would go for the better jutsu use though: in Part 1 kakashi takes quite a bit of time explaining how people can use jutsu inefficiently. Unlocking the Mangekyou took a lot more time in earlier Part II too. I would simply put my money on "kakashi mastered sharingan". Though its probably a combination of both: increased reserves and better handling of the sharingan.