A racist gang took only 10 seconds to kill black teenager Stephen Lawrence and then "casually" walked away, the Old Bailey heard today.
Reeling from two stab wounds the A-level student "ran for his life", hospital worker Royston Westbrook told the jury.
He was the first of three eyewitnesses who gave their accounts of the night Mr Lawrence was killed in Eltham, south east London in April 1993.
Mr Westbrook told the jury that he initially thought the teenager had only been punched.
He said: "It was so quick, it really was quick - it was about 10 seconds - and my impression going away from that was that they managed to punch him and that was it."
He said Mr Lawrence got back to his feet almost as soon as he was forced to the ground.
Mr Westbrook added: "He basically crossed over the road and ran for his life up the hill."
He said the four or five white youths who had staged the attack then just walked away.
"They stood there for a few seconds and then walked off towards Dickson Road casually."
Gary Dobson, 36, and David Norris, 35, both of south London, deny murdering Mr Lawrence.
Mr Westbrook told the court a group of white youths "collided" with Mr Lawrence and his friend Duwayne Brooks.
He said: "They just collided - that's what it looked like. They were just heading towards each other and that was it."
The eyewitness, who was on his way home from working at Grove Park Hospital that night, did not see any weapon.
Mr Westbrook added: "From my viewpoint, it was a completely unprovoked attack. They did nothing to justify it."
A youth who got on the bus with him said: "It looks like they got him because he was black, doesn't it?"
Frenchwoman Alexandra Marie, who was was working in England as an au pair for six months at the time of the murder, told the jury that Mr Lawrence did not fight back when he was attacked.
She was waiting at a bus stop with Mr Westbrook when Mr Lawrence was killed.
She said: "There were some white men who were like kicking him and holding him at the same time, but the young man didn't reply. He tried to protect himself."
Joseph Shepherd was also at the bus stop, travelling home from his then girlfriend's house.
He knew Mr Lawrence by sight because he lived on a neighbouring estate.
Mr Shepherd described the white men "shouting and cheering" as they attacked Mr Lawrence and Mr Brooks.
Prosecuting, Mark Ellison QC asked him: "What happened when they met?"
Mr Shepherd replied: "A load of fists and then they just bundled in on top of them."
Mr Brooks managed to pull free, but Mr Shepherd said he saw the group "bundling" on top of Mr Lawrence.
He said there were "a load of punches and kicking as he was on the ground".
Once he got home that night, Mr Shepherd tried to make sure that Mr Lawrence's parents were told what had happened.
In cross examination by Timothy Roberts QC, for Dobson, Mr Shepherd agreed that the attack had taken around ten seconds.