Myron Robert Alf Felise assaulted the 18-year-old after an incident at the intersection of Wellesley St and Queen St early on the morning of Saturday 27 January.
Seconds before the beating Eli had fired a water pistol out of a car window, striking Felise on the back.
The older man believed he had been shot and advanced on Eli.
In November Felise, 30, pleaded guilty to manslaughter.
He was sentenced today by Justice Gerard van Bohemen in the High Court at Auckland.
It is not the first time Felise has been before the courts for his part in a brutal killing.
In 2008 he and six others were charged with murdering Manurewa liquor store owner Navtej Singh during a robbery.
While only one of the group - Anitilea Chan Kee - pulled the trigger, all seven were charged because police said they were party to the killing.
After a high profile trial only Chan Kee was found guilty of murder.
But today Felise stood in the dock unable to avoid his fate - prison.
Before Justice van Bohemen delivered the sentence Felise had to listen to victim impact statements from Eli's family.
He showed no emotion, keeping his head down throughout.
'You landed six punches'
His oldest sister Chanelle Armstrong spoke first, addressing the court in te reo to begin.
"It's been a little over a year since we buried my brother… in that year I've had a lot of things I wanted to say to you Myron," she said.
"You landed six punches, six - such small number, and such a heavy consequence.
"With every blow, you took something from me.
"Blow one, you took life… you decided to teach a young boy a lesson, you appointed
yourself judge, jury and executioner that night and you handed out a life and death sentence."
Armstrong explained that Eli was adopted into her family as a baby.
He was the biological son of her aunt.
"There was never any question about his belonging," she said, referring to him as her comrade.
She said Eli was "an amazing uncle" and would have been an equally amazing father.
"Blow two - you took his future," Armstrong said.
Eli had left school and had enrolled in a performing arts course.
He had a job, had saved for a car and had many plans for his future.
"You took that from him," she told Felise, speaking of her heartbreak at not seeing Eli marry, have children and nurture a family.
"You took that from all of us.
"Blow three, you made the memories of him finite."
Armstrong spoke of seeing the CCTV footage of the fatal attack.
"You keep beating him, you keep killing him," she cried.
"I walked into the hospital room and I saw my brother lying on a bed… his body was broken beyond repair… he was dying in front of us.
"Those are the memories you gave to us Myron."
She spoke of the moment Eli died, with a room full of family - each of his mothers taking a hand.
"We watched as he left our world, we cried and our hearts broke," she said.
