An ex-footballer was Tasered by a PC for six times longer than standard, before being kicked - leaving bootlace prints on his forehead, a jury heard.
Benjamin Monk is charged with the murder of Dalian Atkinson during an altercation in Shropshire in 2016.
His co-accused, PC Mary Ellen Bettley-Smith, is charged with assault.
Opening the trial, prosecutors read witness statements which claim Mr Atkinson was kicked or struck by the officers after falling to the ground.
PC Monk and 31-year-old PC Bettley-Smith, officers with West Mercia Police, arrived at Mr Atkinson's father's house in Meadow Close, Telford, shortly before 01:30 BST on 15 August after neighbours had reported Mr Atkinson acting strangely and shouting in the street.
When the officers arrived, PC Monk attempted to deploy his Taser when Mr Atkinson, who had serious health problems, opened the door of his father's home, acting erratically and claiming to be the Messiah.
It failed and Mr Atkinson then came out of the property and went to the end of the drive. PC Monk deployed a second Taser cartridge, which again failed.
The prosecution said Mr Atkinson then punched the glass pane in his father's door, which shattered, leading to a further confrontation with the officers and PC Monk deploying his Taser for the third time.
Prosecutors said the default setting for a Taser is five seconds but PC Monk, 42, continued to press the trigger, overriding the system for 33 seconds.
The third cartridge was effective, incapacitating Mr Atkinson who then fell to the ground.
While he was unresponsive, jurors heard the police officers "set about him".
PC Monk kicked him in the head with such force imprints of his bootlaces were left in two parts of Mr Atkinson's forehead, while PC Bettley-Smith used her baton to strike him "a number of times" while he lay still in the road, the court was told.
Summarising witness accounts, prosecution counsel Alexandra Healy QC said one thought Mr Atkinson was unconscious "because of the speed with which he collapsed.... pinning his arms under his body when he fell".
Another described how "tentative" kicks by PC Monk were followed by "a final massive and powerful kick" as Mr Atkinson lay motionless on the floor.
Ms Healy said of the witness: "He described the motion as similar to the sort of kick that would have been required to move a ball up field with significant force.
"He said at the same time the female officer was striking the man with her extendable baton."
Other officers were called to the scene after PC Bettley-Smith pushed her emergency activation button.
Ms Healy said PC Mark Bedford, who was on scene first, had seen her "raise her police baton over her shoulder and strike Dalian Atkinson three times around the waist area".
Another officer, PC Ben Wright, said he had witnessed PC Monk with his "right foot rested on Dalian's head", she added.
Both officers, who jurors heard were in a relationship at the time of the incident, deny wrongdoing. However, it is the prosecution's case their use of force was excessive and sustained while Mr Atkinson posed no threat.
Ms Healy said PC Monk was an experienced police officer of 14 years and would have known he risked causing Mr Atkinson "really serious injury" by kicking him in the head.
She said PC Monk had not been acting in self-defence but had been "angry" to have been "put in fear by this man".
"He chose to take that anger out on Dalian Atkinson by kicking him in the head."
PC Bettley-Smith too, she said, "was not acting in self defence or in defence of her colleague but also taking out her anger on a man who had earlier put her in fear, with the weapon she had been entrusted with to use lawfully".
Ms Healy said the officers were "entitled to use reasonable force to protect themselves" and their conduct prior to the discharge of the third Taser cartridge was not criticised.
However, she urged jurors to "consider with great care" the defendants' case they feared for their safety and were therefore entitled to use such force.
The court was told Mr Atkinson remained handcuffed when he went into an ambulance as a police constable "was concerned that Mr Atkinson might be feigning illness".
The striker, who had a long sporting career at a number of clubs including Ipswich Town, Sheffield Wednesday, Aston Villa and Manchester City, died at about 02:45 on the morning of the altercation.
He had been suffering with high blood pressure, heart disease and end-stage renal failure, the court was told.
The prosecution said although pathologists agreed his underlying health conditions meant Mr Atkinson was "at a greatly increased risk of dying", he would have survived "were it not for the third Taser deployment and the kicks to his head".
PC Monk denies murder as well as an alternative charge of manslaughter. PC Bettley-Smith denies assault occasioning actual bodily harm.
The trial continues.
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HM Courts Service