Kwabena Asumadu told a jury on Wednesday at Ipswich Crown Court that he had lost control and didn't know what he was doing when he stabbed Prince Kofi Koomson 13 times with a kitchen knife.
He said he had only relented when Mr Koomson begged him to stop.
Mr Koomson, 22, was found stabbed to death last year on Christmas Eve, at a house he shared with Asumadu, 28, in St John's Place, Bury St Edmunds.
He had moved to Linton Avenue, Borehamwood, from Ghana in March 2006 to join his family, but relocated to Suffolk after getting a job as a mechanic in September that year.
His father, Frances Koomson, is the pastor at the House of Prayer Pentecostal church which holds its services in Manor Way, Borehamwood.
advertisementOn Tuesday, the second day of the trial, the court heard how the victim's father had phoned his son just hours before he was killed, asking him to come to Borehamwood and spend Christmas with him.
His son declined, saying he would instead visit during the New Year holiday.
Asumadu has denied murdering Mr Koomson and said he only realised how many times he had stabbed him after the injuries were listed in a doctor's report.
Asked by his barrister, Michael Corkery QC, if he had any idea what he was doing at the time of the attack, Asumadu said: "No. I was absolutely disturbed. I lost control. I lost my mind. I lost everything."
He said that he had never been violent toward anyone before the attack on Mr Koomson.
Giving evidence on Wednesday, he told the court he admitted manslaughter.
The court has heard that in the weeks before Mr Koomson's death, Asumadu had become increasingly resentful towards him because he was earning more money than him at the car valeting business where they worked in Bury St Edmunds.
On the night of the stabbing, the pair had rowed. Mr Koomson had become annoyed when Asumadu refused to turn down music he was listening and dancing to in a downstairs room.
Asamadu claims Mr Koomson kicked him in the face and had insulted him by saying he was bewitched.
It was after this that Asamadu allegedly picked up a kitchen knife and went back upstairs and stabbed Mr Koomson.
He said that after the attack he had left the house and had thrown away the knife.
The trial continues.