The attack lasted "about a minute'', he said.
Mr Huaki said after the assault, the bleeding driver got out of the car. He recognised him as Mr Hadfield.
He ran to call the police before rushing out to help Mr Hadfield, he said.
Under cross-examination, he told defence lawyer Mike Antunovic the attack stopped when he saw Stark pull Robinson away from the car by using "a bit of force'' before walking away.
Mr Huaki's girlfriend Marissa Robinson told the court the men walked away "casually, like nothing had happened''.
Another witness, Colin Berkett, said the incident lasted less than two minutes.
After the attack happened he saw Mr Hadfield get out of the car.
"I thought he had a blood nose ... but then I was told he was stabbed.''
He told Mr Antunovic he last saw the two young men running along George Street.
Crown prosecutor Ian Murray yesterday (Mon) told the jury Mr Hadfield was stabbed once in the chest, and the knife pierced his heart and lung.
He died the next morning in hospital.
Mr Antunovic said Robinson admitted he stabbed Mr Hadfield, but it was in self-defence.
The trial has been set down for two weeks, and more than 50 witnesses are expected to be called.