Corey Swan, 24, is set to face a sentencing hearing in the district court on October 22 over the brutal assault, which took place at a busy Balgownie intersection.

The court heard on Tuesday that Swan was walking down Ellengowan Crescent just after 5pm on October 25 last year when he saw the man, aged 26, on the opposite side of the road.

Swan crossed the road to confront the man, yelling out "you're a dog" while the man tried to ignore him.

When the victim refused to respond, Swan started following him, continuing to call out "you're a dog".

The pair then reached the Balgownie Road intersection where the man finally replied: "Fine, I'm a dog."

Swan then kicked the victim in the face, causing him to fall backwards and hit his head on the gutter.

He immediately lost consciousness.

Swan saw the man wasn't moving but turned and walked away.

An off-duty police officer who saw the assault immediately followed Swan and arrested him, while other witnesses helped the victim.

While speaking with police, Swan said: "I kicked him, it was a brain snap."

He told officers the man had reported an incident, which caused police to attend his home, and he decided to interrogate him, admitting "I just kicked him straight in the face from where I was standing".

Swan was charged with recklessly causing grievous bodily harm and later pleaded guilty.

The victim was rushed to Wollongong Hospital where he was treated for a fractured skull.

He remained in hospital for eight days, suffering post traumatic amnesia for six days.

Swan was remanded in custody ahead of his sentencing.