A man left his victim with a brain injury after a brutal lockdown attack with a table leg.
Michael Jones, 46, turned on James McCulloch at a flat in Drumchapel, Glasgow, on April 1 this year.
Mr McCulloch, 53, was struck after trying to stop Jones from assaulting his friend Nicola Black.
Jones fled, but later claimed to police: “I don’t remember what happened.”
He faces a lengthy jail-term after admitting assaulting Mr McCulloch to his severe injury, permanent disfigurement and to the danger of his life.
Jones will be sentenced in the New Year.
The High Court in Glasgow heard he initially started arguing with Miss Black, 36, before pinning her to the ground and punching her.
Mr McCulloch pulled him off the woman, but Jones then “turned his attention” on him.
Prosecutor Angela Gray said: “Jones repeatedly struck Mr McCulloch on the head and body with a wooden table leg.
“Mr McCulloch fell to the floor and Jones continued to strike him with the makeshift weapon.”
Police arrived after a 999 call. Mr McCulloch was found in the blood-splattered flat with a “significant” injury above his eye.
The court heard he had bruising on the brain, three fractured ribs, a collapsed lung as well as the head wound.
Miss Black meantime had a fractured nose and a cut cheek.
Jones admitted in court to assaulting Miss Black to her severe injury and permanent disfigurement.
But, initially after being traced by police, he claimed to have woken up with blood on his hands, but could not recall how it happened.
Jones was remanded in custody as the case was adjourned for reports.