The Crown says Carlos Pula took his anger out on an innocent man and killed him with a single punch.
Mr Pula has denied a charge of manslaughter and is on trial at the High Court in Auckland.
The Crown said he punched Reginald Sharma at a party in August last year, causing his death.
Mr Pula's lawyers said it was dark, everyone had been drinking and there was doubt over who threw the fatal punch.
The Crown prosecutor Fiona Culliney told the jury in her closing address that despite Mr Sharma being punched in the early hours of the morning, two witnesses were clear about what they saw.
"Two unshakable identification witnesses pointed the defendant out as the puncher [and] performed photo montages that identified Mr Pula."
The first was woken by his cousin calling out: 'don't bring that gang stuff here'. He grabbed a jumper and headed outside. It was dark but the security light was on.
She said Mr Pula had just been involved in a fracas with another man. Daniel Ruka saw him walk past Mr Sharma.
"Mr Ruka sees that man walk around the car, walk past the deceased, Mr Sharma [who was] minding his own business, a humble man with no beef with anybody that night. And he sees the deceased step slightly back, perhaps trying to let him through unobstructed, and he sees that angry man swing at Mr Sharma and hit him."
Mr Ruka saw the man tie his long hair up in a man-bun as he walked away - a compelling detail that Ms Culliney said added weight to his evidence.
Ms Culliney said the second eye witness, Ruatau Taripo, had been deeply effected by what he saw.
"He repeated a number of times the way the images replay in his mind and that the incident has affected his whole life.
"I suggest what you saw, members of the jury, was a man who has been deeply traumatised from seeing a man killed in front of him."
Mr Taripo was clear about seeing the punch and hearing another person address Mr Pula.
"It was a senseless, motiveless act on an innocent man by someone who was angry because he had been cheap-shotted ... And he took it out on the wrong guy. That's what happened."
Mr Pula's lawyer Mark Edgar said the Crown's two eye witnesses did not hang around to talk to the police and fled the scene.
"These people, individually and collectively - almost to a man, I suggest to you - drank a lot, a lot. So, you think about that issue of sobriety when you consider a witness' account, as to its accuracy as to the recall."
He also spoke of the darkness and shadows at the scene which would make it difficult for any of the witnesses to see who threw the punch.
"It's not just about identifying the perpetrator, which is what the Crown will have you believe, it's about all the other detail amongst the commotion, the dark, the timing [claps his hand] in a second, in a second when this blow was struck."
Mr Edgar also questioned whether the witnesses felt loyal to one side and had changed their evidence accordingly.
Tomorrow the jury will hear Justice Hinton sum up the case before retiring to consider their verdicts.