A judge has described the fatal stabbing of Melbourne woman Laa Chol at an Airbnb party as a "powerful, attacking thrust".
A teenage boy jailed for at least 15 years for Ms Chol's murder appeared via video link on Friday before Victoria's Court of Appeal in a bid to overturn his conviction.
The boy, who cannot be identified because he was 17 at the time, gatecrashed the CBD party in July 2018 and stabbed 19-year-old Ms Chol in the chest.
Ms Chol's fatal stabbing was captured on CCTV.
"It looked to me as a powerful, attacking thrust," one of the three appeal judges said.
The boy's barrister, Paul Smallwood, argued the stabbing arose "somewhat spontaneously" and did not meet the legal threshold for murder.
He said it was not open for the jury to have concluded beyond reasonable doubt the boy intended to murder or cause really serious harm to Ms Chol.
"It was not planned; it was not pre-meditated," Mr Smallwood told the court.
He added that there was no pre-existing animosity between the pair.
The boy was jailed in December 2019 for a maximum of 20 years. He was ordered to serve 15 years before becoming eligible for release on parole.
The jury rejected his plea at trial to be convicted of the lesser crime of manslaughter.
Ms Chol died at an EQ Tower apartment she had rented on Airbnb for a weekend with friends.
The boy gatecrashed the party. Ms Chol discovered her phone was missing and kicked the intruders out.
She was stabbed during a scuffle, part of which was captured on CCTV, in the lift lobby.
The knife penetrated her chest cavity and heart, and she stumbled back into the apartment and collapsed.
Prosecutor Patrick Bourke QC, who opposed the appeal bid, said the stabbing was a deliberate and forceful act committed at close range that left an 8.5cm wound.
He also said CCTV footage showed the boy had full view of Ms Chol's body and would have known he was stabbing her chest, a vulnerable area.
"It's not a situation where he's flailing around with a knife in a fight," Mr Bourke said.
"It is a very deliberate, forceful blow to her body. He plants his left foot and it's one motion."
Mr Bourke also said the boy had already been kicking and kneeing Ms Chol before he stabbed her.
"He made a decision to escalate the attack," the prosecutor said.
A decision will be handed down at a later date.