A promising rugby league player died after his jugular vein was severed and he went into "irreversible shock", a pathologist has told the court.
Vincent Angene Skeen, 18, is on trial accused of the murder of 17-year-old Luke Tipene in the early hours of November 1, 2014.
The Crown case is that their respective friends initially fought before the victim and defendant squared off.
It is alleged Tipene punched Skeen, knocking him down, but the murder accused sought revenge, smashing a bottle and using the jagged shard to stab the teen in the neck.
Pathologist Dr Paul Morrow, who gave evidence this morning from Vermont via audio-visual link, catalogued the various sharp and blunt-force injuries suffered by the victim.
He began with the most serious wound to the left of Tipene's neck, which was up to 12cm deep and about 5cm in length.
Morrow told the court a sharp instrument had passed through the neck, caused an incision in the jugular vein and hit the voice box in a "slightly downward motion".
Tipene was rushed to hospital and almost immediately went into the operating theatre but died at 4.40am.
Morrow said he essentially died from "irreversible shock as a result of the stab wound".
"As blood pressure falls as a result of bleeding, that causes inadequate circulation to tissues of the body . . . and as a result of that deprivation of effective circulation to the body for a critical interval, the body went into shock and death resulted from that," he explained.
Brian Dickey asked the pathologist if it could be labelled "bleeding to death" and Morrow agreed.
The fatal wound, he said, would have been caused by a shard likely to be 10cm long and ruled out the broken bottle neck in its current state which had been shown to the jury.
"That particular beer bottle neck does not have an extension like that, which is not to say at some point it couldn't have had such a thing that broke off that puts the bottle in its current position," Morrow told the jury.
As well as the fatal injury, Morrow detailed a dozen others- one as long as 16cm in length - but described them all as superficial skin wounds.
The jury were also told of several "cuts and scrapes" to Tipene's face, abdomen, arms and legs.
Yesterday, two men gave evidence of watching the street brawl from a Grey Lynn balcony.
Allen Winton said the dynamics of the fight were clear.
"The taller guy was trying to defend himself, the shorter guy was very aggressive . . . clearly he wanted to do harm," he told the jury.
"The shorter guy was charging towards the taller guy with his arms swinging in a roundhouse sort of motion and the taller guy was backing up with his hands up in the air, retreating back."
Neither witnesses saw a blow connect with Tipene.
Winton said his view was obscured as the duo went behind a tree beside the road.
But when they became visible again he saw "the taller guy clasping at his neck and I can see blood starting to drip down his arm and chest".
Defence counsel Lorraine Smith said her client - who was 16 at the time - may be guilty of manslaughter but lacked the requisite intent to be convicted of the more serious charge.
The trial continues.