"Vincent Skeen got knocked over a couple of times by Luke Tipene, there's not much doubt about that. It made Vincent Skeen angry; really angry. Maybe it embarrassed him in front of his mates," prosecutor Brian Dickey said.
The Crown case is that the defendant found a full beer bottle, which he smashed on the ground, leaving only the bottle's jagged neck in his hand.
Skeen and Tipene then squared off again, the court heard.
"Vincent Skeen had the better of the re-engagement because he had a smashed beer bottle to use as a weapon. It seems Luke Tipene realised that and sought to get out, to disengage, to back away," the prosecutor said.
"He thrust the protruding blade, the shard of that weapon, deep into Luke Tipene's throat."
Defence lawyer Lorraine Smith said her client accepted what he did was wrong.
"When Vincent Skeen was 16 years old he picked up a bottle and he hit another boy with it. That boy tragically died and it changed the lives of two families forever," she said.
"The Crown must prove Vincent had a conscious appreciation of the risk of death and decided to take that risk."
She said there was "huge doubt" over whether that was the case and urged the jury to remember everything happened very quickly.
"The whole Crown case is based on Vincent Skeen having time and appreciation to know exactly how that bottle had been broken, then to decide to use it knowing Luke's death was a probable consequence," Smith said.
"The Crown saying Vincent was aiming for Luke's throat ... is a complete overstatement of the evidence. The other very realistic possibility is that Vincent was swinging out blindly without any intent to connect with any particular part of the body."
Smith stressed Skeen had been struck in the head twice before causing the fatal blow and had been drinking that afternoon too, both of which could have clouded his judgment.
