Andrew Lee, the 33-year-old Diamond Creek man accused of murdering teenager Patrick Cronin in an alleged one-punch attack, was today granted bail in the Victorian Supreme Court.

Mr Lee’s parents have agreed to pay a $350,000 surety with strict bail conditions attached.

The decision was handed down after the Justice Karin Emerton viewed CCTV footage in the application, which the prosecution argued showed a "cowardly attack from behind on a defenceless victim not involved in the fight".

Patrick Cronin, 19, died after acting as a mediator in the brawl outside Windy Mile hotel in Diamond Creek pub on April 16.

Patrick Cronin, 19, died after a coward punch' outside a pub at Diamond Creek in April. (AAP)

He left the pub with friends, and was taken to hospital the next day where his condition continued to deteriorate.

His family made the decision to turn off his life support on April 18.

During Mr Lee's application for bail, his lawyer said he had never intended to punch Mr Cronin, and was instead trying to hit the teenager’s friend. He said there may have been another contributing cause of death .

Prosecutor Peter Rose, QC, said Mr Lee had joined a fight he had no involvement in, and had three-and-a-half years of Muay Thai martial arts training, which he claimed contributed to the force of the punch to Mr Cronin.

Mr Cronin's parents outside the Supreme Court today. (9NEWS)

He called the punch "a somewhat cowardly attack from behind".

Mr Cronin’s family were in court today and spoke about their son.

"Everything Patrick has done in his life he's done with determination, courage, fairness and love, it's just so unfair what has happened to him," his father Matt said.