One-punch accused was defending pal: court

A man accused of killing a teenager in a Melbourne pub brawl claims he was only trying to defend a mate who was involved in the fight.

Andrew William Lee, 34, has pleaded not guilty to the manslaughter of Patrick Cronin, who died after a fight outside the Windy Mile Hotel at Diamond Creek in April last year.

It's alleged he unlawfully punched the 19-year-old to the temple, causing his death, but Lee's lawyer presented another view at his trial opening on Wednesday.

"He had a pal in that group." defence lawyer Peter Morrissey SC told the Victorian Supreme Court.

"Something brings him in (to the fight).

"The Crown has to prove he was not stepping in, quite lawfully, to defend another person."

Mr Morrissey urged the jury to reserve their judgement until they'd heard all the evidence, and to block out media coverage of the case.

"It doesn't follow that because a 19-year-old fellow has died that there has to be a punitive consequence," he said.

But prosecutor Richard Kinnane QC said Mr Cronin was trying to steer a friend away from the brawl when he was unlawfully struck by Lee.

"Patrick Cronin was assisting one of his friends away from the altercation when he was punched to the temple area by the accused man," he said.

"Mr Cronin was not in any way aggressively involved in the fighting."

The punch didn't knock Mr Cronin down, and he managed to walk back to a friend's house, but his condition quickly deteriorated.

He died of a brain haemorrhage in hospital on April 19, 2016, the day after the punch.

The jury will visit the Windy Mile Hotel on Thursday to view the crime scene before court resumes in the afternoon.