A witness described hearing a loud clap sound up the driveway and seeing Carlos Pula run past him shortly before police arrived at an Auckland house party.
Pula, 23, is on trial in the High Court at Auckland charged with the manslaughter of 25-year-old Reginald Sharma at a Mt Roskill home last August.
The Crown alleges that Pula delivered a single, fatal upper cut to "an absolutely innocent bystander".
Andrew Falconer said he arrived at the party at Haughey Ave after drinking for a few hours at the Gemini bar in Otahuhu. He said he was welcomed inside by a man he nicknamed "True Blue".
Falconer said he later saw True Blue take a "cheap shot" at Pula in the back of his head as he was looking the other way. He said the accused appeared angry after.
Falconer then went to check on the car parked out on the road. He described hearing a "clap" sound "like someone had been hit" up the driveway.
Falconer said he then saw Pula ran straight past him, and shortly after that, Stanley, who was at the party with Sharma, also walked right past him, holding a "massive" knife behind his back.
It was at that point that Falconer said he decided it was time to leave, and as he was walking to the car, the police arrived. And it was then that he learnt someone really had been hit, and that it had been Sharma.
Earlier today, in her opening statements, Crown prosecutor Fiona Culliney told jurors that on the night of August 19, Pula got "really drunk" at a 21st birthday party at a Haughey Ave address.
"After hours of solid drinking, he decided to hit a completely innocent man in the face," she said.
Pula allegedly upper cut Sharma on the left side of his face, causing an artery to split at the back of his head, resulting in a brain bleed and his death.
The Crown argued Sharma had been "minding his own business" and didn't provoke him in any way prior to the attack.
Culliney said Sharma was "an absolutely innocent bystander" and the accused had taken out his anger on him for no reason whatsoever after being involved in a fight just minutes earlier at the property.
The Crown said two people at the party who witnessed the blow, one of whom was sober, will be called to give evidence.
Pula's defence lawyer, Mark Edgar, told the jury the events of the night started at the Gemini bar in Otahuhu and ended up at Haughey Ave, involving a number of people drinking.
Edgar boiled down the defence case to two main issues. The first being the credibility and reliability of the witnesses set to be called.
The second issue is focused on medical evidence.
"Pula cannot make a fist despite what the Crown might say," Edgar said.
The trial has been set down for two weeks.