It is alleged a brawl started between a group of Tongans - which the Moalas were part of - and two Samoans.
In court today one of the pair, Clifford Matoka, said he was out on the smokers' deck with his friend Daniel Leota when he heard raised voices speaking a language he did not understand.
When he realised the animosity was targeted at him, he suggested they leave the bar but he said he was punched moments later.
The Crown said a bottle was used in the attack and an artery was nicked in Mr Matoka's neck, causing significant blood loss.
Mr Shaw told the jury that after the initial flashpoint had subsided, George Moala then attacked Mr Matoka as he was being helped downstairs by bouncers.
The rugby player later told police he had retaliated because he believed the man had punched his sister.
"I remember being punched, then was unconscious and then woke up outside the club holding a T-shirt to my face," he said.
Mr Leota told him not to panic before informing him he had been wounded.
"So I felt my neck and the blood sprayed out," Mr Matoka said.
During cross examination George Moala's lawyer Paul Wicks, QC, said the fracas had been caused because Mr Leota had been shouting "one out" at other patrons in the bar.
Similarly, Siua Moala's counsel Mina Wharepouri suggested it had happened because they had "drunkenly called out other people in that area for a fight".
But Matoka - who admitted drinking nearly a litre of gin before heading into town - said that was not the case.
"I don't call people out. I'm not that type of person," he said.
Mr Shaw said the jury would be shown CCTV footage that showed George Moala attempting to flee the scene before being apprehended by police.
George Moala, who has represented Tonga at under-20s level, signed a two-year contract with the Blues after an impressive season last year with the Auckland NPC team.
The trial, before Judge Rob Ronayne, is expected to last two more days.
