Pathologist Dr Marjorie Turner said the dead man, Paul Cunningham, also had a distinctive bruise on his arm which could have been caused by the shaft of the club.
Dr Turner said she was called to the flat in Haghill, Glasgow, to view the body, where Mr Cunningham, 35, had been found lying beside a mattress in his living room, before performing a post mortem the following day.
The High Court in Edinburgh heard the bedroom of the flat had been given over to the cultivation of cannabis plants.
Dr Turner said Mr Cunningham had been struck at least eight times causing "extensive" fractures and bleeding inside his skull. Tests also showed he had a blood alcohol level three times the driving limit, which might have impaired his ability to defend himself. His body also revealed traces of cannabis use.
The trial also heard of an earlier row at Hogmanay in which a golf club was used.
Shop worker Gavin Williamson, 25, said he had been seeing in the New Year with friend Stuart Patterson when a man he didn't know came to the door. Later the man ignored Mr Patterson when he told him he should leave and Mr Patterson threw him out, after a struggle in the hallway.
Stuart Patterson, 27, and wife Kimberley Reid, 25, both of Glasgow, deny murdering Mr Cunningham in his flat on February 8.
It is alleged Mr Cunningham was beaten to death with a golf club before the pair made off with cannabis pants and £20.
Mr Patterson and Ms Reid are also accused of attempting to defeat the ends of justice by trying to arrange a false alibi for him.
Both face charges of having offensive weapons: a golf club in the case of Mr Patterson and a bottle in the case of Ms Reid.
The two are also accused of being concerned in the supply of herbal cannabis in January and February this year. The trial continues.