The murder trial of musician Molemo "Jub Jub" Maarohanye and his co-accused Themba Tshabalala is expected to continue in the Protea Magistrate's Court on Monday.
In March, the court heard that Tshabalala was responsible for the 2010 crash that claimed four lives.
"He is responsible for causing the accident," eyewitness Mphumelelo Vezi told the court.
Vezi was a passenger in Tshabalala's car when he allegedly collided with Maarohanye's car in Soweto on March 8, 2010.
They were allegedly drag-racing their Mini Coopers along Mdlalose Drive in Protea North, Soweto, when one of the cars ploughed into a group of school pupils.
Vezi told the court that Tshabalala attempted to overtake while a minibus taxi was approaching about 40 metres in front of them.
When he returned to the left lane to avoid colliding with the taxi, he clipped Maarohanye's car, which resulted in the accident.
He told the court Tshabalala's car hit a group of pupils as it rolled after hitting a kerb. Four boys were killed and two others severely injured.
Maarohanye and Tshabalala are on trial for murder, attempted murder, and driving under the influence of alcohol and drugs.
State prosecutor Raymond Mathenjwa is expected to cross-examine Vezi on Monday when the trial continues.