Well there is this scan from the Naruto quiz book.
That's a vague statement that doesn't really confirm either stance.
For one, the statement doesn't say the opponent's chakra is injected in the target; it says that Genjutsu is a state where one's chakra is being manipulated within the brain, with the Brain being...
- The house of the Yin half of the chakra (aka the consciousness)
- comprised entirely of the Yang half of the chakra in every cell of the brain (physical energy)
- "Chakra," rather, its components are completely in charge of all bodily functions, from all senses, to all the organs, to even the skin.
So basically, Genjutsu is a state where the energy that resides in all bodily functions and the consciousness is manipulated from within the brain.
Disrupting the chakra in the brain is also in reference to one's own agitated chakra rather than someone else's, as the actual chapters where Naruto recalls Jiraiya's flashback suggest.
Needing a power that surpasses the opponent is also vague and not really supported.
Because GJ is never shown, stated, or implied to be resisted with literal power, rather GJ resistance that can be amplified with superior Dojutsu, forms with greater GJ resistance, or just greater GJ resistance due to being a specialist.
Otherwise, none of these no named Uchiha with MS should be capable of putting Kurama under GJ for long if at all, yet the story suggests they're the only ones in the entire village that would be able to.
So yeah, this is one of those statements that only makes sense in that way, with none of the context of the story.