Power said the woman entered her boyfriend's bedroom and, after speaking to him, wandered through the house looking for the other woman.
The third party, meanwhile, had shut herself in another room.
The defendant was "quite clearly angry and upset", Power said, and went back to her boyfriend's bedroom and threw the other woman's property on the floor.
She demanded the man return some of her belongings and he duly loaded them into her car.
As she was leaving, however, the man confronted her, believing she had stolen something, the jury was told.
"How did she react?" Power said.
"The Crown alleges ... she has driven the car at him, hit him and he's ended up on the bonnet and she's started driving down the gravel driveway."
It is alleged the man smashed the windscreen in a bid to stop the defendant.
Power said she did stop the vehicle, in doing so throwing the complainant off the car and on to the ground, before she drove away.
A six-minute phone call she later made to police would form part of the Crown's evidence, the court heard.
In it, the defendant said she had caught her boyfriend sleeping with someone else and, after an argument, he had jumped on the car and smashed the windscreen.
Counsel Anne Stevens QC said there was no assault — her client simply wanted to leave the address and her boyfriend jumped on to the bonnet to stop her doing so.
The man thought the defendant had his phone, Stevens said, and he was concerned its contents would expose him "as a cheat and a liar".
The defendant was accused of stealing the woman's wallet, which had never been found following the incident.
While Power accepted the case was circumstantial, he said theft was the only "reasonably inference".
Stevens rejected that.
"[The defendant] had no interest in [the woman's] wallet, didn't know what it looked like, didn't touch it," she said.
The trial, before Judge Michael Crosbie and a jury of seven women and five men, is expected to last a couple of days.
