Deborah Kearney witnessed four attackers "rain blows" on 15-year-old Keelan Wilson just yards from his home in Strathfield Walk, Wolverhampton, on May 29, 2018.
Miss Kearney rushed over to Keelan's side, after alerting police, where she said he "never said a word but just looked at me", Wolverhampton Crown Court was told.
He had been stabbed more than 40 times and was confirmed dead at hospital within an hour. Four 19-year-old men are standing on trial accused of his murder.
The trial so far:
Miss Kearney had met Keelan and an associate fixing a car just before 11pm that night on Strathfield Walk, in the Merry Hill area of the city, as she walked home.
Her friend, Rupert Doley, ended up calling a taxi for Keelan as they couldn't get the red Citroen working.
She became aware of a group of men walking down the road after she reached her gate. By that time, the taxi had arrived.
At first, Miss Kearney thought nothing of this group. But she became "anxious" once one of them shouted Keelan's name and they start running, jurors were told.
Miss Kearney said: "There were definitely four of them, maybe five. They appeared to be 15 to 18-years-old, in their late teenage years.
"They shouted 'Keelan, Keelan, Keelan' as they got level with me. It was one of them that shouted his name. I described it like a whooping war cry, shouting for somebody's attention.
"It was very eerie hearing that sound as they shouted his name. As they started to run, two of them had extendible telescopic weapons that came out of nowhere."
Asked by Mr Michael Duck QC, prosecuting, about what happened next, she said: "They struck the taxi and I heard windows smash.
"At that point, having got at the taxi and dragging the two lads out, blows were being rained. I walked away to get my phone and call police."
She added: "I went straight over to him [at which point the attackers had gone]. I knelt down by him. I was talking to him but he never said a word. He was just looking at me.
"I think other neighbours came out to assist.
"There was a gentleman who lives on the corner that came out with a blanket to put over him."
Keelan was declared dead in hospital at around midnight.
Nehemie Tampwo, of Fern Grove, Bletchley; Sasa, of Long Ley, Heath Town; King, of Chelwood Gardens, Bilston; and Pennant-Phillips, whose address cannot be published for legal reasons; all deny a single charge of murder.
The trial continues.