A man lost his temper with his partner after a night out before he "beat and kicked and stamped her to death", a jury has heard.
Raj Sidpara, 50, is accused of murdering his partner Tarnjeet Riaz - also known by her maiden name Chagger - at his home in Leicester on 6 May.
He denies murder, but at an earlier hearing on 18 October, pleaded guilty to manslaughter, admitting to killing her, the jury was told.
The murder trial opened at Leicester Crown Court on Wednesday.
The court heard Ms Riaz did not live with Mr Sidpara but had been a regular visitor at his bungalow in Tarbat Road in Leicester since their relationship began some months before her death.
Steven Bailey, prosecuting, told the jury: "This case is about a man who lost his temper with his partner at the end of a night out, and who beat and kicked and stamped her to death in a confined space in his bedroom once he got her home at the end of night."
The jury was given details of some of Ms Riaz's injuries, including multiple fractured ribs, bruising and lacerations to her lips.
A combination of injuries to her head and to her chest were the cause of her death, Mr Bailey said.
Mr Bailey added the prosecution's case was that Mr Sidpara inflicted many or most of the injuries to Ms Riaz "while she was unconscious or helpless".
"Once he'd inflicted those injuries, he might even have gone to sleep while she died on the floor on the side of his bed in the small hours of morning of Monday 6 May," Mr Bailey added.
The prosecution said Ms Riaz was dead by the time Mr Sidpara called for an ambulance "at around lunchtime".
During the 999 phone call, Mr Sidpara was told how to give Ms Riaz CPR, which had failed.
Mr Bailey told the jury the CPR had never succeeded because "by the time Mr Sidpara had called 999, she was already cold and stiff and her jaw locked shut".
Mr Sidpara told the call handler she had fallen over while drunk and suffered injuries that had caused her to bleed, the jury heard.
However, Mr Bailey said the prosecution's case was that Ms Riaz's injuries were caused by "sustained, persistent, deliberate, and intentional application of severe force".
The jury was told how the couple had been out at a bar the evening before, and after Mr Sidpara drove them back to Tarbat Road, they went to see a neighbour, where they drank some more before going home.
Both were "heavy drinkers", Mr Bailey said.
But that night, CCTV from the bar footage showed Ms Riaz "got drunker than Mr Sidpara" and that he was "steadier on his feet" and even able to drive them back to Tarbat Road "without issue".
Sarah Vine KC, defending Sidpara, said the jury would need to consider whether Mr Sidpara's "alcohol dependency" caused him to behave the way he did when he killed Ms Riaz.
The trial continues.