A man accused of running down his ex-girlfriend's former lover outside her NSW home told her "You made me do this", a court has heard.
Kieran Eugene Joseph O'Connor has pleaded not guilty to murdering Andrew Sobolewsky by crushing him under his Mitsubishi Lancer on June 18, 2012, in Bullaburra, in the Blue Mountains.
On the first day of O'Connor's Supreme Court trial, Crown prosecutor Mark Hobart SC said the accused man had had a violent run-in with ex-girlfriend Lauren Hilton hours before the alleged murder.
But although she called the police, she needed a favour from O'Connor involving his car and he returned to her house that afternoon.
It was as O'Connor was preparing to drive off that another of Ms Hilton's ex-boyfriends, Mr Sobolewsky, turned up.
"He says the deceased said, 'Oi, I'm going to have you mate', had a furious look in his eye (and) ran in front of the accused's car," Mr Hobart said on Tuesday.
A neighbour who ran to the scene of the collision to help, Belinda Ednes, told the court how she squeezed Mr Sobolewsky's hand as he lay dying.
She described seeing a trail of blood on the roadway.
"The lady was on the other side of the road, screaming," Ms Ednes said on Tuesday.
"(O'Connor) was saying, `It's all your fault. You made me do this.'"
The jury heard that O'Connor had told police he tried to swerve and brake to avoid hitting Mr Sobolewsky, but that the deceased had jumped onto his bonnet like a "stuntman".
But Mr Hobart said experts would give evidence during the three-week trial that cast doubt on this explanation.
"The Crown will seek to show beyond reasonable doubt that the deceased was in front of the car, and the accused knew he was there and ran over him - accelerated and ran over him," Mr Hobart said.
He said the accused was angry that Ms Hilton was leaving him and that relations between the two men were "very tense".
A paramedic who tended to Mr Sobolewsky told the court Ms Hilton had told her that he was her ex-boyfriend, "but we've been mates for ages".
The trial continues.