Crown prosecutor Brian Dickey pointed to evidence of Skeen grabbing a bottle from the back of a ute, which he allegedly smashed and used to attack Mr Tipene.
But defence counsel Lorraine Smith questioned that witness's testimony and cited others who had suggested her client had actually grabbed the glass shard from the ground.
"What's absolutely certain is that the defendant Vincent Skeen stabbed, punched or thrust a jagged broken beer bottle into Luke Tipene's throat, embedding it as far as 10 to 12 centimetres into the neck," Mr Dickey said.
The blow pierced the victim's jugular vein and he lost too much blood to survive.
Mr Dickey stressed to the jury that the Crown did not have to prove any element of premeditation in the alleged murder, only that the defendant knew the risks of an attack with the lethal weapon.
"[Skeen] achieved what he set out to do. He got him and he got him real good. He killed him," the prosecutor said.
"What more do you want for murder than that?"
Mrs Smith said the jury must take into account her client was 16 at the time, was drunk and had just been punched when he lashed out.
"Vincent Skeen accepts and he's always accepted he's guilty of homicide. He accepts he did an unlawful act and his act killed another young man," she said.
"What he doesn't accept is that when he struck out at Luke Tipene he attempted to kill Luke or appreciated for one moment Luke might die."
While the Crown said text messages sent by the defendant after the incident showed only worry for his own situation and no concern for the victim, the defence disputed that.
Skeen immediately told friends he had "caked it" - or "messed up" - and despite hiding from police, was said to be in a state of disbelief when the seriousness of the situation dawned on him.
Justice Mark Woolford will sum up the case tomorrow morning before the jury retires to consider its verdict.
