They both admitted a raft of charges at an earlier court appearance - Efaraima Fiti for unlawfully interfering with a vehicle, two counts of possessing a knife in public and aggravated robbery, Potaua for aggravated robbery and failing to stop when pursued by police.
Judge Bridget Mackintosh sentenced Efaraima Fiti to two years' imprisonment and Potaua will serve 11 months' home detention.
Mr Sharma's BMW car was stolen as well as his cellphone and $42 worth of pizza.
Judge Bridget Mackintosh told the court that at about 11.15pm on a Friday night in January, the four offenders walked from town up Milton Rd, scoping out a dimly lit area.
She said Efaraima Fiti "seemed to be committed to hurting someone and it was just a matter of who".
The group had made a plan for the girls to stall the driver and the boys to hide in bushes before they bashed Mr Sharma. Potaua ordered the pizzas and when Mr Sharma pulled up she told him she was going inside to get money for the pizzas.
Mr Sharma was "king hit and blindsided". Potaua got into the pizza delivery man's BMW and at one point was driving right for Mr Sharma, who was on the ground. Luckily he managed to get out of the way and went for help, the judge said.
Potaua drove the four of them to a Flaxmere home where they ate the pizzas and disposed of the rubbish.
The judge said they told the police they were bored and wanted a car.
She said Mr Sharma was a hard-working man who had two jobs. He wrote in his victim impact statement that initially he had thought New Zealand was a beautiful place to live but now felt isolated and weary of his work, which he remained doing.
He was out of pocket $400 after the incident.
Potaua was spotted driving the car on the expressway and was pursued until eventually pulling over.
Judge Mackintosh said each of the four offenders had been placing the blame on each other, which she put down to their youth and that they had been "basically, rarking each other up".
Ms Mitchell said both Efaraima Fiti and Potaua, and the other two offenders, were all active participants in the bashing - Efaraima Fiti using violence and bashing the pizza delivery man and Potaua acting as a decoy and getaway driver.
She said the victim was inherently vulnerable by virtue of his work and the "savage and prolonged attack ... [which] did not cease when the victim was on the ground".
Efaraima Fiti had been in custody since his arrest and his lawyer, Matthew Phelps, said his client had limited English after moving to New Zealand from Samoa when he was 13. His parents lived in Auckland and he lived with his aunt and uncle in Flaxmere.
The judge said they were good people and Efaraima Fiti had not done right by them, becoming involved in gangs and drinking and smoking.
Mr Phelps said Efaraima Fiti had been aged 17 for just months before the offending and it was his first time before the courts.
He said it was poor decision-making and although his client's pre-sentence report assessed him as having little insight into his offending, it did not mean he did not have remorse.
Potaua, who spent 20 days in custody following her arrest, was now living at her mother's address with strict conditions.
Her lawyer, Eric Forster, said "hearing the clang of the prison door behind her has had a sobering effect".
He said his client showed remorse and had written an apology letter for Mr Sharma.