A thug stabbed his sister's ex-boyfriend five times, which left him with critical injuries.
John Morris pounced on Douglas Bamford outside a flat in Motherwell.
The 42-year-old lashed out amid Mr Bamford hurling abuse at his sibling Wendy.
Morris struck Mr Bamford repeatedly on the torso and thigh in front of Wendy's neighbours.
Morris pled guilty yesterday at the High Court in Glasgow to the assault to Mr Bamford's severe injury, permanent disfigurement and danger of life.
The court heard Wendy and Mr Bamford remained friends following end of the relationship.
Morris was at the property when Wendy and Mr Bamford were drinking together, on July 1, 2021.
Mr Bamford hurled insults at Wendy and he left when he was asked.
But, he continued to shout abuse at her from outside as Morris watched.
Prosecutor Angela Gray said: "Morris confronted Mr Bamford in the street.
"They started to fight as neighbours looked on.
"During the altercation, Morris was seen to strike Mr Bamford repeatedly on the body with a knife."
Morris fled the scene as Mr Bamford was rushed to hospital.
Miss Gray added: "Mr Bamford was found to have sustained a total of five wounds, four to his torso and one on his thigh.
"A stab wound on the torso caused the medical team particular concern.
"A CT scan was performed to assess the severity of the injuries.
"Mr Bamford was admitted to High Dependency for observation. His condition at that stage was described as critical."
Mr Bamford signed himself out of hospital against medical advice and he will be permanently scarred.
Morris handed himself into police four days later.
It was revealed that Morris' previous convictions include violence, drugs and disorder.
Sentence was deferred pending background reports until next month by judge Lord Armstrong.
