Board Thread:Episode Discussions/@comment-25319479-20170920093317/@comment-2112031-20170923123258

UltimaDude wrote: The Wikia Editor wrote: To be fair, it's entirely possible that Naruto did that out of habit rather than necessity. It's entirely possible that Naruto could already produce a Rasengan without a clone by the time Shippuden began, but continued doing it that way because he was used to doing it that way. Nope, he did it out of necessity, not habit. During his nature transformation training with Kakashi, he became salty that Kakashi could create a Rasengan without the aid of a clone and stated that he still needs a clone to make one That still only really indicates that Naruto couldn't perform a Rasengan without a clone at that moment in time. We don't know whether he had actually trained at performing the technique without clones prior to that point.

It should also be noted that did actually perform a Rasengan without clones during his fight with Sasuke at the end of part I by using the demon fox cloak to contain the Rasengan.