Throughout the anime series, it has been established that Killua is stronger than Gon, while the latter has a higher ceiling. Using his abilities as a Transmuter, Killua can create a lightning-based aura. ... While Gon possesses more raw strength, in almost every other aspect, Killua is superior.

Can Gon beat Killua in fight?

Yes, Gon has the strength advantage, but that's about it. Killua is mentally more of a veteran, and Gon does not really surpass him in any category in combat. And with Killua's Godspeed, I don't think Gon would be able to even touch Killua.

Does Gon have more potential than Killua?

Killua is said to hold tremendous potential, comparable to that of Gon himself. Over the course of time, he's only gotten stronger and by the end, he'll be one of the strongest in the series.