UFC heavyweight Nelson kicks the ref

UFC heavyweight Roy Nelson has sensationally kicked referee John McCarthy, after he was late to stop his fight against Antonio Silva.

Nelson, who is friends with his beaten opponent 'Bigfoot' Silva, was upset at being forced to continually punch him as he lay unconscious.

Best known for his ridiculously strong chin, Nelson showed he also has plenty of empathy, commenting that he was upset for his friend.

“Bigfoot is my friend, he has to go to his family. To me, I already know I already won, so what's the sense?” he said afterwards.

He may face sanctions from UFC Brazil over the incident.

Watch the incident in the video above.