Two schoolboys accused of killing a partially-sighted man were seen kicking the victim as he lay on the floor, Sheffield Crown Court has been told.
Mr Greenwood died from a head injury
A witness said she heard "muffled thuds" as one of the boys, who cannot be named, kicked Colin Greenwood near a tram terminus in the city in April.
Mr Greenwood, 45, of Southey Green, later died from a brain injury.
Both boys, now aged 14 and 15, deny murder and causing grievous bodily harm with intent.
Witness Lisa Collier said she saw a hooded boy grab Mr Greenwood by his clothes and pull him down on to the floor before aiming at least three or four kicks to his head.
"From where I was it looked like he was directly kicking that person in the head," she told the jury.
Miss Collier said she heard "muffled thuds" as the boy kicked Mr Greenwood "forcefully" before he and another boy, who she did not see taking part in the attack, left the scene at Middlewood tram terminus in the north of the city.
After the attack, Miss Collier watched as Mr Greenwood used a set of railings to pull himself to his feet and made his way "unsteadily" towards where she was standing.
She learned the next day that Mr Greenwood had died.
A schoolgirl, giving evidence by video link, said she had seen both boys, who she knew, kicking Mr Greenwood on his head and body "quite a few times".
Earlier in the trial, the court heard the boys launched the attack after Mr Greenwood kicked out at one them as they pretended to punch him and threatened to stab him with a penknife.
Mr Greenwood was only taken to hospital later in the day after he fell as he got off a bus. He died the next morning.
A post-mortem examination found his death was due to a brain injury but also revealed areas of bruising and broken ribs.
The case continues.