A jury has been told Anna Eiao Browne killed Carly Stewart in a single strike with a massive knife, at a nail and eyelash party.
Browne has been charged with murder over the death, which happened in Te Atatu in October last year.
Prosecutor Nick Webby opened the Crown's case on Monday, describing how Browne allegedly plunged the knife with so much force it went deep into the side of 36-year-old Ms Stewart's head.
He said the knife cut through the jugular and went into her throat.
Defence lawyer Marie Dyhrberg told the jury Browne does not deny causing Stewart's death. But she said Browne is not guilty of murder because she did not have the necessary murderous intent at the time the fatal blow was struck.
Mr Webby told the jury of nine women and three men it was a "deliberate and conscious act", and the injuries inflicted caused Ms Stewart's death.
Browne and Ms Stewart were friends before the party, and even called each other "cuz", said Mr Webby - and while Browne only knew two of the women at the party, she turned up early clutching bottles of vodka and Jim Beam bourbon.
Unlike others at the party, Mr Webby said, Browne continued drinking and became abusive and aggressive. She allegedly picked fights with several people at the party, including Pākeha woman Justine Evans, allegedly for having a Rarotongan boyfriend.
Browne was causing so much disruption she was eventually asked to leave. But shortly before the fatal stabbing, Ms Stewart and Browne were seen grabbing each other by the scruff of the neck in the hallway.
The victim allegedly said to her friends: "I'll be the bigger woman, I'll walk away." But minutes later the defendant walked to the kitchen and grabbed the biggest knife in the butcher's block - which had been used to make guacamole.
She put the 25cm blade behind her back and returned to the lounge. Mr Webby said Browne's eyes were fixed, and in a low tone called Ms Stewart's name before she stabbed her in the face with a "quick forceful movement" - so quick, some didn't even see the knife and thought that Browne had punched her victim.
As Ms Stewart lay dying with her friends trying to stem the flow of blood, Browne fled the house. But she returned five minutes later and denied she had stabbed the victim.
Emergency calls played in court
The court was played recordings of two one-on-one calls made after the attack.
The victim's sister Corrine Stewart made one of the calls as friends and family tried to stem the flow of blood from the wound in Stewart's face.
Screaming can be heard in the background as she described the wound: "I'm not sure if it's in the face but there's a lot of blood. It's all down her clothes."
As they pressed down on the bleeding, paramedics told them to press harder, but blood kept spurting out.
In another phone call to a Christchurch paramedic, Carly's cousin Patricia Stewart can be heard saying "the bitch is running down the road", referring to Browne.
Patricia is heard describing how Browne got drunk and stabbed Stewart in the face. The paramedic tells her to press down firmly and not to take it off to look.
She later described how Browne returned, but reassured the paramedic Browne no longer had a knife and everyone was safe.
However Patricia was also heard telling everyone that she didn't want Browne to leave. As Carly's condition deteriorated, Patricia is heard to say: "She's losing consciousness now - where is the f*****g ambulance?"
Paramedics urged her to lay her cousin on her back but at that point the police turned up, and the phone call was terminated.
Defendant blames drugs
The jury heard Browne would blame the effects of PCP or 'angel dust', even though toxicology reports on a urine sample showed no trace of the drug. In fact, when she claimed she had consumed 2 grams of PCP, Mr Webby said that would have been enough to kill her.
Browne at another point allegedly claimed she had consumed 2 grams of methamphetamine, which Mr Webby said would also have been enough to kill her. Browne had consumed methamphetamine, but only several days earlier.
Mr Webby said Browne claimed her drinks had been spiked with "wazz", also known as GHB, but there was no trace of the drug in her urine sample.
Browne's murder trial is expected to take two to three weeks. Up to three dozen witnesses have been called.