The man who knocked Simon Cramp unconscious in an early morning assault in Sydney's CBD was "wild with aggression", a friend says.
Mitchell Gardiner, 29, was with his friend Simon Cramp, 27, outside a fast food outlet on Sydney's George Street in the early hours of June 3 last year when they witnessed a melee erupt between several males.
As the pair looked on, Mr Gardiner told a Sydney court on Thursday, a man described as David Angelos asked them: "What the f*** are you looking at, ****?"
Angelos and a male friend then walked towards them and began attacking them, Mr Gardiner said at the 24-year-old's Downing Centre trial.
"I was waiting for a barrage of punches so I had my hands up trying to protect myself."
After defending himself against Angelos's friend, Mr Gardiner said he turned to see Mr Cramp holding his hands up with his palms facing outwards.
"Simon was obviously motioning at them just to stop. There was no reason for them to be attacking us."
Angelos then threw a "haymaker" at Mr Cramp, hitting his jaw and creating a loud thud, Mr Gardiner said.
"It was a right hand (punch) with all his might ... He was wild with aggression."
"Poor old Simon went unconscious instantly. He wasn't able to protect himself.
"Simon's arms went straight down beside him, almost lifeless ... his eyes went straight back into his head."
As his friend fell, Mr Gardiner said his chin was tucked towards his chest and his head then struck the ground.
"There was blood coming from his mouth, his ear and the back of his head."
While Angelos admits to punching Cramp he has pleaded not guilty to causing grievous bodily harm with intent.
The trial continues.