A Wild World Club Challenge has seen Cowboys prop James Tamou dropped with a straight right punch but North Queensland emerged comfortable victors over Leeds.
Tensions erupted in the 72nd minute of a physical clash in Leeds.
Tamou resented a grapple tackle from Leeds prop Keith Galloway and threw a short left as he rose to his feet.
Another Leeds prop, Mitch Garbutt, ran in and landed a right hand flush on Tamou's nose which opened him up immediately.
There were cries of a cheap shot from Cowboys players as Tamou was half looking at Galloway when he was hit.
Tamou was taken to the sheds bloodied and Garbutt sent off to a standing ovation from the 19,778 strong crowd.
While the Cowboys lost the battle, they won the war.
Australia whitewashed the World Club Series after a Johnathan Thurston masterclass defeated a gallant Leeds outfit 38-4.