Cane Norton Kelland, 28, initially called the 18-year-old victim of Pacific Island heritage "boy" before twice referring to him as "n....." and repeatedly hitting him.
Judge Jim Large said the question of whether it constituted a hate crime was easily answered.
"Realistically there’s no other conclusion I can properly reach given the use of that particular word on two occasions," he said.
On November 20 — only six months before the death of Trinity Catholic College pupil Enere McLaren-Taana in an unrelated incident — Kelland was at the bus hub in Great King St, intoxicated by alcohol and cannabis.
He approached the victim, who was sitting on a bench, and asked whether he was Maori.
"You think you’re a gangster, n.....," he said, before trying to force a drink on the teenager.
"Have a drink, n......"
When the victim declined the beverage, Kelland threw a punch.
The teen blocked the blow but was unable to evade the next one, which connected above his right eye.
Kelland then shoved him against a concrete wall and continued the attack, using his knees while continuing to swing with his fists, the court heard.
Security officers pulled the defendant away but were unable to fully restrain him.
Court documents described how Kelland taunted the victim and aimed another flurry of punches, striking the teenager in the left side of his head.
He eventually walked away and was arrested nearby, later admitting he "took his frustrations out on the victim and lashed out".
Counsel Andrew Dawson said Kelland had no memory of the incident but stressed he had no previous racially motivated crimes to his name.
He told the court the defendant was homeless at the time and had limited support in the community.
Judge Large said the homelessness issue was "a sad factor in our community today" and also referred to a report which detailed Kelland’s turbulent upbringing.
"[It] indicates you’re a young man who’s fallen through many cracks after being discharged from Oranga Tamariki care," he said.
"That’s very sad. Nonetheless, your violence that day is not acceptable."
In a statement, the victim said he had fully recovered from his injuries and now avoided the bus hub.
"I’m not angry about what happened, I’m just shocked," he wrote.
Kelland was convicted of injuring with intent to injure and jailed for 18 months.
