Bol Mangok was on trial in the Victorian Supreme Court, charged over the death of Kose Kose at Bourke Street in the early hours of October 30, 2022.
Prosecutors alleged Mr Mangok ran from a nightclub to confront Mr Kose and his two associates, who had been assaulting one of his friends.
Mr Mangok allegedly stabbed the two men in the chest and leg before stabbing Mr Kose five times.
Police arrived while the fight was still underway and the two groups, including Mr Kose, fled.
The 20-year-old was found critically injured in the doorway of a nearby shop and taken to hospital, but died an hour later.
A post-mortem found a knife had pierced his heart, left lung, diaphragm and spleen.
Mr Mangok was charged with Mr Kose's murder but he took the case to trial, arguing he was acting in self-defence.
After deliberating for just over a day, the jury on Tuesday afternoon returned not guilty verdicts to the charges of murder and the alternative manslaughter.
They also acquitted Mr Mangok on the other offences of intentionally causing serious injury, recklessly causing serious injury, intentionally causing injury and recklessly causing injury.
10°C