Gardai are continuing to question a man in connection to the death of Cathal Sweeney in South Dublin.
It is understood two men and Mr Sweeney watched the Ireland vs Wales match in Mr Sweeney's flat in Terenure, South Dublin, before a row occurred.
At 5.45pm Gardai and Emergency Services were called to the flat at a house in the Ashdale Gardens area of Terenure.
The victim was rushed to St James's Hospital with serious head injuries. He was subsequently pronounced dead.
A man in his 30s was arrested at the scene and is currently detained under Section 4 of the Criminal Justice Act, 1984 at Terenure Garda Station. He can be detained for up to 24 hours.
The scene is preserved pending a forensic and technical examination and the state pathologist has been notified.
The deceased man was a member of local rugby club St Marys.
A member of the club said he had been around the club but that his brother was more closely involved.
Local Fine Gael councillor Edie Wynne said the community was shocked.
"It is normally a nice, quiet area. It is a terrible thing to happen."
The State Pathologist's office has been alerted and the potential crime scene preserved pending a forensic examination.