User blog comment:Martialmaniac/Zoldyck power ranking/@comment-10528819-20150616191559/@comment-5780397-20150617175315

Right, but Chrollo tracked him with the intent to kill him, so he was forced to fight back seriously.

I think you are underestimating Killua and overestimating some of the PT members. Some of them are undoubtedly weaker than Hisoka, while Killua's abilities are very flexible and allow him to go toe to toe with opponents stronger than him (Youpi took a lot of damage but his endurance was far superior to that of humans).