Christina Abbotts was found dead in a bed in Crawley after friends raised the alarm when she failed to turn up for her own birthday party in London in May.
The sex worker, who advertised her services under the name Tilly Pexton on Adultwork.com, had been struck 13 times on the back of the head with the black object – normally used with a mortar to crush ingredients – and was also possibly strangled, Lewes Crown Court heard on Tuesday.
Ms Abbotts, who had studied at Cirencester and Oxford, had been housesitting for a friend.
Freelance financial consultant Zahid Naseem denies murdering Ms Abbotts sometime between May 25 and 26.
Prosecutor Christopher Tehrani told jurors the 48-year-old stayed in the flat for 12 hours after she died, sending pornographic pictures and films to another sex worker and pretended to be unconscious when police broke in.
He said: “The assault Christina Abbotts suffered which resulted in her death was brutal, savage, unnecessary and pointless.
“Unknown to many of her friends and family she was a sex worker. In some quarters she would be described as a high-class escort.”
The court heard Naseem, who lives in Amersham, Buckinghamshire, with his estranged partner and two children, and Ms Abbotts met on several occasions and arranged to see each other in Crawley before her birthday celebrations.
No-one heard from Ms Abbotts after midday on May 25, which was “very unusual”, and when she did not arrive at her party, friends rang the police.
When officers arrived at the scene and broke down the door, Naseem was found lying motionless on the sofa with his eyes flickering.
He claimed the last thing he could remember was “passing out” after the pair met up in the flat, the court heard.
But Mr Tehrani said: “The prosecution say there was nothing wrong with him. He was play acting.”
Naseem’s fingerprints were found in blood on the side of the bath, on a meat cleaver in the kitchen and on Ms Abbott’s iPhone, as well as in a half-filled bath with a knife at the bottom and other knives on the sofa.
Mr Tehrani said there was no sign of forced entry and “only someone with the powers of Spiderman” would have been able to access the flat on the top floor of the block.
A post-mortem examination found she died of blunt-forced trauma to the head, sustaining 11 tears and two bruises, and there were signs of attempted strangulation on her neck.
The trial continues.