Police officers are combing through CCTV to identify who delivered the blow that knocked him unconscious in the street.
At 3.30am on Sunday, two groups of men were leaving a pub on Parramatta’s Church Street when an alcohol-fuelled argument erupted, leading to an all-out brawl.
NSW Police used pepper spray to break up the group.
A 21-year-old man was found unconscious after being punched in the head.
He was taken to hospital in stable condition.
Police are now appealing for witnesses to help them find those responsible.