Darren Fresco said he asked Pistorius immediately after the sunroof shooting if he was “mad” and told how the runner “just laughed” at him.
Pistorius denies shooting the gun in the car, although two witnesses have now said that he did.
Mr Fresco said the athlete had asked him to take the blame for a gun being fired accidentally by Pistorius under a table in a busy Johannesburg restaurant.
Pistorius, 27, is on trial for murder over the death of girlfriend Reeva Steenkamp on Valentine’s Day last year, and also faces two firearm charges for shooting in public and a third for illegal possession of ammunition.
Pistorius, the first double-amputee runner to compete at the Olympics, pleaded not guilty to all four charges against him. He specifically denies that he fired the gun in the car, his defence team has said.
Throughout yesterday’s court proceedings in Pretoria, Pistorius mostly sat with his hands in his lap, only changing position to make notes.
Mr Fresco, who said he was driving the car during the alleged sunroof shooting in late 2012, and a former girlfriend of Pistorius’, Samantha Taylor, have both testified the athlete shot his gun out the car. Mr Fresco said the group was pulled over, for the second time that day, and Pistorius was furious with an officer for handling his gun, which he had left on the passenger seat.
“You can’t just touch another man’s gun,” Pistorius said to the officer, according to Fresco. “Now your fingerprints are all over my gun. So if something happens, you’re going to be liable.” Later, Pistorius shot out of the sunroof, Fresco said.
“Without prior warning, he shot out the sunroof,” Mr Fresco said. Defence lawyer Barry Roux pointed out that Miss Taylor had a different version.
Mr Roux questioned Mr Fresco on the incident at a Johannesburg restaurant in early 2013 when he handed his gun, a Glock 27 .40-caliber, under the table to Pistorius and it fired.
Mr Fresco said Pistorius asked him to take the blame for the incident, which he did, because he feared bad publicity. Mr Fresco said he had warned Pistorius the gun was “one-up,” meaning it had a bullet in the chamber.
Pistorius maintains he was the only one to shout and scream on the night of the killing. But prosecutors say Ms Steenkamp screamed during an argument and then during the shots, with witnesses testifying to hearing a woman’s screams.
Prosecutors say Pistorius therefore knew who he was shooting at. They have hinted that the bullet that hit Steenkamp in the head was one of the last of the four shots, giving her time to yell out.
Pistorius denies murder, saying he shot Steenkamp by mistake thinking she was an intruder. The trial continues.