Jack Woodley was killed after he left Houghton Feast in October 2021, by a group of teens who were "out looking for serious trouble".
The 18-year-old was punched, kicked, stamped on and stabbed in the back, while the group "prevented him from escaping and prevented other people from helping".
Jack, who had told his attackers he wanted to go home and did not want to fight, died in hospital.
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Ten youths, now aged between 14 and 18, were convicted of murder last month, after a trial by a jury at Newcastle Crown Court.
At the start of their sentencing hearing today, Jack's grieving mum Zoe McGill bravely stood in the witness box and said her son was her "cheeky blue-eyed boy" and what happened to him was "unbearable".
She told the court the whole family would be "forever haunted about how horrific Jack's injuries were".
Fighting back tears, she added: "This has ruined our family's lives and life will never be the same again without Jack."
Ms McGill said Jack had been "looking forward to the future".
Jack's father John, in a statement read to the court by Prosecutor Mark McKone QC, said that his heart was "broken into a million pieces".
He said his son "did not stand a chance" during the cowardly attack, in which the "pain and fear Jack endured must have been unthinkable".
Nicholas Lumley QC, defending the teen who inflicted the fatal wound, said it was a single blow which happened in a "matter of seconds" and was not due to a "pre-existing desire for revenge".
Mr Lumley said the youth feels "remorse, shame and regret" and "will be rehabilitated" in custody.
Liam O'Brien, defending the youngest of the killers, said: "He was just 14 years and two months at the time and still 14 at the point of conviction.
"He appreciates entirely he needs to be punished for his part in the murder of Jack Woodley".
The court heard some of the teens handed character references to the court, one was described as "well mannered and polite" and another "acted out of character".The youths will be sentenced on Friday.