Update: Simone Mastrelli, 30, has been jailed at Preston Crown Court for three-and-a-half years for the assault of Sean Cox, 53, outside Anfield ahead of a Champions League tie between Liverpool and Roma last April.
Earlier: An Italian national has pleaded guilty to assaulting Liverpool FC supporter Sean Cox outside Anfield stadium.
Father-of-three Mr Cox, 53, from Dunboyne in Co Meath suffered catastrophic head injuries in the attack ahead of the Champions League semi-final first leg tie between Liverpool and AS Roma on April 24 last year.
He has been recovering at the National Rehabilitation Hospital in Dun Laoghaire after he spent four and a half weeks at the Walton Centre in Liverpool, a specialist neurological unit for brain injuries, following the incident.
Simone Mastrelli, 30, from Rome, appeared from custody at Preston Crown Court today and entered a guilty plea to unlawfully and maliciously inflicting grievous bodily harm on Mr Cox.
A separate count of violent disorder was allowed to lie on file by the UK Crown Prosecution Service after it accepted his not guilty plea to the charge.
Sentencing by the Recorder of Preston, Judge Mark Brown, will follow shortly.
Mr Cox's wife, Martina, was in court for the hearing.
Mastrelli was extradited to the UK last month after being arrested on a European Arrest Warrant in his home country.
Another Roma fan, Filippo Lombardi, 21, was cleared of inflicting grievous bodily harm on Mr Cox in October, though he was jailed for three years for violent disorder.
A third man, Daniele Sciusco, 29, from Rome, admitted violent disorder ahead of the match and was jailed for two-and-a-half years in August 2018.
The court heard that Mr Cox was knocked to the ground, unconscious, by a single punch from Mastrelli after he and his brother, Martin, had "sadly by pure coincidence" entered the path of a group of Roma's "Ultra" fans including the defendant.
Footage of the incident in Walton Breck Road, near The Albert pub, was played in court and shows Mastrelli initially confronting Mr Cox with his arms raised.
Lombardi then comes to the fore and raises a belt as Mastrelli moves back and then, from Mr Cox's right-hand side, Mastrelli forcibly punches him to the face.
A witness described the incident as a "sudden and unprovoked attack" and a "sickening sight".
Keith Sutton, prosecuting, said Mastrelli immediately moved away as Mr Cox lay motionless on the ground, and checked that his face covering was in place as he blended in with a group of Roma fans.
Mastrelli left the scene but later returned to Walton Breck Road and had taken steps to change his appearance by removing his face covering, his hood and the jacket he had been wearing.
He then entered the ground to watch the match.
Mastrelli had flown in from Germany with a friend and later met up with other Roma fans, including Lombardi and Sciusco, at Manchester Airport railway station.
He was said to be wearing the recognised "Ultra" uniform of a dark jacket, either black or light blue jeans and black or white footwear.
Mastrelli was already seen to be wearing his face covering - a balaclava - shortly after the group arrived at Liverpool Lime Street station just before 5.30pm.
They were later seen in nearby Hanover Street about 40 minutes later, with a number of them wearing their hoods up with their faces covered, before the group of up to 60 walked towards Anfield - with Mastrelli frequently seen at the front.
A witness noticed the group in Venables Street, close to Walton Breck Road, and thought they were "angry" and concluded "there was going to be some trouble" as he began to film them on his mobile phone, said Mr Sutton.
The prosecutor added:
Shortly afterwards, Martin Cox heard "a lot of noise" in Walton Breck Road in what he described as "shouting and chanting, but not in a good way".
Mr Sutton said: "He recalls turning to his brother to discover he was already on the floor. He had not seen what happened but, as he attempted to assist him, he too was kicked and fell to the floor."
Mr Cox was treated at the scene and then taken to the trauma unit at Aintree Hospital, where he fell into a coma.
Later the same evening he was transferred to the Walton Centre where doctors operated to alleviate bleeding on the brain.
Mr Cox could not be moved home to Ireland until the end of May, and on August 18 had started to open his eyes spontaneously and make some verbal sounds, the court heard, but there was still no response to any external stimuli.
He was transferred to the National Rehabilitation Hospital in Dun Laoghaire on October 3 with a "profound" brain injury with global cognitive and communicative impairment.
Mr Sutton said: "He is unable to communicate his needs, wants or wishes ... he is unable to walk and requires assistance with all activities of daily living.
"He has a reduced awareness of his own current difficulties.
The court heard that, prior to the attack, Mr Cox was a "busy husband and father of three children", employed as a sales director, who enjoyed a wide circle of friends and many active interests.
Mr Sutton said: "The reality is that he is unlikely to live independently again."
Mr Cox's daughter, Shauna, entered the witness box to read a victim personal statement as Mastrelli watched from the dock, flanked by an interpreter.
She said: "Before this brutal and vicious attack my dad was a fit and confident man, a man of integrity with a huge passion for life who represented everything which is good. A mentor, a proud family man with great community spirit.
"This violent and unprovoked attacked left Dad in a dire situation. We don't know how he will progress and that really frightens us.
"We hope and pray every day to see improvement in our dad. The focus is on getting Dad the proper care he needs.
"My dad went to watch his beloved team, Liverpool, and he never came home."
Asked by Judge Brown how her father was in spirit, she replied: "He definitely has not lost his personality. He is a fighter."
The court heard that Mastrelli had been placed under house arrest in Italy since October and had attended several court hearings to contest his eventual extradition.
Alison Gurden, defending, said Mastrelli was a family man himself and was "distraught" at the suffering he had caused.
She said: "He is a man who over the past few months has appreciated the impact it has had. He is a Catholic and has taken Communion since the incident. He has attended church whenever possible to try to atone.
"He was not aware of the extent of the injuries to Mr Cox until he got back to Italy but he was aware as soon as he punched Mr Cox he had done something wrong."
Judge Brown will pass sentence this afternoon.