"You described [in a police interview] the victim dropping back to the ground, lying on his front [and] you ran back into the crowd and kicked him.
"You described it ... as 'taking a place kick in rugby'.
"You wanted the victim to be 'done with' ... knocked out."
While she could not give any credit for a guilty plea, Judge Cook said she did take into account his age and that he had a limited criminal history.
Harrison was in full-time employment and there was "benefit" in continuing that.
"It's important that you address the way you behave ... you clearly have some talent in terms of being a talented sportsman and you're in full-time employment."
Conditions of his supervision sentence were to attend an assessment for a departmental programme as directed; attend and complete counselling, treatment or programmes as directed to the satisfaction of a probation officer; and not to possess, consume or use any alcohol or drugs not prescribed to him.
He was curfewed between 7pm Friday and 6am Monday, beginning this week, and was also sentenced to 180 hours' community work, 10 months' supervision and ordered to pay $796.96 reparation at $100 a fortnight and witness costs of $100.