Knuckle was clearly too strong and skilled for Gon to contend with outside of perhaps his Jajanken, whilst Killua was in turn no match for Shoot prior to the 30 days' training and learning Godspeed. After the training, however, Gon became strong enough it was implied his Jajanken would kill Morel, who ought to be above Knuckle and Shoot.
In short: Gon's Jajanken (Palace infiltration) >/>> Morel > Knuckle/Shoot >> Pre-Palace Gon/Killua > Genthru