The trial has opened in the Dublin Circuit Criminal Court of four young men accused of the manslaughter of a Dublin student in August 2000.
Brian Murphy, from Clonskeagh, was punched and kicked to death outside the Burlington Hotel.
The 18-year-old suffered brain damage and multiple facial injuries and died of heart failure en route to hospital, just before 5am on 31 August 2000.
The four accused are Dermot Laide (22) from Castleblayney in Co Monaghan, Desmond Ryan (22), Andrew Frame (22) and Sean Mackey (23), all from south Dublin.
All deny manslaughter and a second charge of violent disorder.
Court hears of 'intensive' attack
The court was told that the attack took place as crowds poured out from Club Annabel. It was a short, intensive attack of considerable violence and there was no justification for attacking him, the jury heard.
Prosecuting counsel Edward Comyn said the incident began with an argument between Mr Murphy and Mr Frame, but it was not clear what it was about or who started it.
At some stage the fight grew and Mr Murphy became surrounded by a group of four to six people, he added.
It was this group who punched and knocked the victim to the ground and kicked him in the body and head, the jury was told. The prosecution says the four accused were part of the group.
Earlier, Judge Michael White said the trial was expected to last three to four weeks and most of the prosecution witnesses would be drawn from the Dublin 4 and south Co Dublin area.