Albert Snowball, 22, of Perth, died after he fell from a window during a fight at a warehouse in Brunswick in Melbourne's north on November 27, 2005.
Boxer Khalid Baker, then 18, and his co-accused AB, who cannot be identified, are on trial in the Supreme Court after pleading not guilty to his murder.
In his opening address, crown prosecutor Peter Rose SC said Baker and AB had been involved in violent and serious unprovoked attacks at the party that night.
Mr Rose said Mr Snowball was on the stairway landing when he apparently said something to enrage Baker and his friend Ali Faulkner, causing them to rush upstairs towards him.
Baker then began violently attacking Mr Snowball, while Faulkner was restrained by an onlooker, he said.
AB joined in the attack, punching Mr Snowball repeatedly, he said.
Mr Rose said one or both of the accused pushed Mr Snowball, causing him to tumble out of the window and hit his head on the footpath four metres below.
He was rushed to the Royal Melbourne Hospital in a critical condition suffering severe brain damage from a fractured skull. He died two days later.
Mr Rose described the attack as "furious and sustained", saying the pair acted together to seriously injury the victim.
He said AB told police he was just a metre away when he pushed the victim. While he knew there was a window behind him, did not believe he would fall through.
AB's lawyer Bill Stuart said his client, who was drunk at the time, told police he was just breaking up a fight and did not mean to injure Mr Snowball.
"This guy came up, started yelling at my friend. My friend was trying to hit him. I broke it up," the accused told police.
"It was wrong that I pushed this guy but it was a fight. I was trying to break it up because it would've led to something else if I would've left my friends there."
Mr Stuart asked jurors to consider what caused Mr Snowball to fall out the window, whether the fall was accidental, whether AB intended to cause inflict serious injury or was just a "peaceman" caught up in a fight.
The trial before Justice Simon Whelan continues.
©AAP 9 Apr, 2008Give us more TpT !! Lets import them from other countries, because they don't breed quick enough here.