Crown prosecutor Andrew Tinney, SC, told the Supreme Court the drunk Mr Hardy, 21, a third-year arts student who lived at the university's Trinity College, had been a "stumbling and bumbling mess' when Kyle Zandipour slung him to the ground, kicked him in the head three times and stomped on him.

Mr Hardy had a blood alcohol level of 0.27 when he came across Mr Zandipour and his friend, Matthew Bell, sitting at an outside table at the St Kilda Road McDonald's eating their food just after 1am on Saturday, October 18, 2014.

Mr Tinney said Mr Hardy had not been aggressive in any way when asking to borrow his phone before Mr Zandiopour attacked him.

Mr Hardy was later rushed to The Alfred hospital but died within the hour from head injuries.

Mr Zandipour, 29, has pleaded not guilty to murder.

In his closing address to the jury, Mr Tinney said Mr Zandipour's attack on Mr Hardy had been "a truly frightening display of violence, excessive unbridled violence and unnecessary".

"A display of violence and superiority and he had been able to inflict those fatal injuries in only six seconds in a manner which gave Joshua Hardy absolutely no chance," Mr Tinney said.

The prosecutor said while Mr Zandipour might have been smaller than Mr Hardy, he had had two advantages over his alleged victim.

He said the first advantage was that Mr Hardy had been highly intoxicated and was a stumbling and bumbling mess.

The second advantage, Mr Tinney said, was Mr Hardy had not been expecting to be attacked.

"The evidence indicates Joshua Hardy had never even said a word to the accused," the prosecutor told the jury.

"Joshua Hardy was looking at Matthew Bell who was right in front of him.

"The accused was out of his view, you might think, to the left hand side or at best in the periphery of his view and the attack came from there, out of his sight, this sneak attack.

"Even a sober person faced with a sudden and unexpected application of force coming from out of his view, may well have thudded into the ground much as Joshua Hardy did.

"But he was not a sober person, he was drunk, he was unsteady on his feet, he was befuddled by alcohol and he had absolutely no chance whatsoever.

"From the first micro-second of that attack, he was completely and utterly helpless and he was like a rag doll being slung into the ground head first."

Mr Tinney said that after the drunk, helpless Mr Hardy was thrown to the ground, he was set upon by Mr Zandipour for absolutely no reason whatsoever.

Mr Zandipour later told police he was scared because of Mr Hardy's body language, the way he was staring, his aggressive tone of voice, how he towered over them and would not answer any questions.

He thought Mr Hardy could have been on drugs and it was a tense situation.

"I didn't intend to hurt him, I didn't go out looking for trouble or anything like that," Mr Zandipour said.

The trial, before Justice Lex Lasry, continues.