James Legg, 31, was convicted on Tuesday, after a trial at Wood Green Crown Court heard how he violently targeted his victim, in her 20s, at her home in Camden on November 15, 2021.
The pair, who were known to each other, had spent the day together before the victim asked Legg to leave as he had been taking drugs and alcohol and she was concerned about his behaviour.
But, after Legg put his coat on, he went to her room armed with a knife and “launched a sustained attack”.
When Legg went to the kitchen to fetch another knife, she barricaded herself in the bathroom.
He tried to get in but ended up leaving before the police arrived.
The victim’s flatmate called 999 and Legg was “quickly tracked down and arrested”.
During police interviews, he did not provide any reason for the attack and answered “no comment” to all questions put to him.
Police Constable Andrew Fisher who led the investigation said: “This was a horrific incident which left the woman with significant stab injuries.