A mother murdered her "helpless and vulnerable" seven-month-old daughter two hours after care workers left her alone with the child, a court heard.
Jennifer Crichton, 35, of Leyland, Lancashire, subjected baby Amelia to a "violent physical assault" when carers left, Preston Crown Court was told.
Prosecutors said the baby suffered "catastrophic" head injuries.
Ms Crichton, who denies murder, claims Amelia went "limp" after letting out "an almighty scream" while waking up.
Christopher Tehrani QC, prosecuting, told the court the defendant's story was discredited by expert medical examination which excluded any accident, natural disease or medical condition.
Tests showed Amelia had suffered a skull fracture and bleed on her brain, with Ms Crichton offering no explanation as to what had happened.
Medical analysis concluded she had been subjected to a "violent physical assault" immediately before her collapse as a result of "striking or throwing" against a hard surface as well as bodily shaking, the prosecutor said.
Injuries included damage to nerve fibres in the brain stem, a complex skull fracture to the right side of Amelia's skull and bleeding to her right eye.
The injuries were "strongly supportive" of being due to a "deliberately inflicted head injury" caused by "significant blunt force", Mr Tehrani said.
Ms Crichton was receiving help under a care order to look after the baby at her home on Slater Lane, Leyland, but an hour and 20 minutes after her support worker left the property at 23:00 on 19 April, Ms Crichton rang for an ambulance reporting her daughter was not breathing, jurors heard.
Amelia was taken to The Royal Manchester Children's Hospital but two days later doctors concluded the child would not recover from her "catastrophic" brain injuries and life support was withdrawn.
Ms Crichton was arrested four days after her daughter's death.
The trial continues.