The teenager was driving a stolen car when he crashed into another car and collided with a pole. (ABC News)

A Melbourne teenager had been on probation for just nine days when he caused a deadly, high-speed crash that killed his friend.

The 17-year-old faces a stint in jail over the crash and for bashing a man so badly that the victim was left with lifelong disabilities.

The teenager, who can’t be named for legal reasons, faced the County Court on Friday and pleaded guilty to charges including culpable driving causing death and intentionally causing serious injury.

Chief Judge Amanda Chambers rejected calls by the boy’s barrister to limit his sentence to four years in a youth prison.

“This is not a sentence of four years detention,” she said.

Then aged 16, the teen was nearly three times over the drink-driving limit when he drove a stolen SUV through a red light and struck another car, causing a catastrophic crash last May.

The stolen car spun out of control and slammed into a traffic light pole at the intersection of Dohertys Road and Derrimut Road in Tarneit.

A passenger in the stolen vehicle, 16-year-old Kevin Olenga, died in hospital a week later.

The death of Kevin, the third of eight siblings, devastated his family.

“I’m so fearful of accepting his loss … I feel so bad, I cry all night,” his mother Bora Mireye said in a victim impact statement.

Defence barrister Naomi Smith said her client had been released on probation by the Children’s Court nine days before the crash over other crimes.

Boy punched, stomped on man in car park attack

Three months earlier, the boy participated in a group bashing outside a Flemington housing tower which put two men in hospital.

Crown prosecutor Nanette Rogers SC said the teenager approached one victim, 36-year-old Valentino Arop, and “king hit” him from behind.

The attackers kicked and stomped on Mr Arop for 10 minutes, causing lifelong brain injuries.

Mr Arop requires a walking frame and is unlikely to ever work again, the court heard.

“It was gratuitous violence inflicted on a person who was defenceless,” Ms Rogers said.

Ms Rogers, a veteran barrister, said she was not aware of a comparable case where a young person was before the courts on two very serious charges relating to different events.

Judge Chambers said other teenagers found guilty of culpable driving had been jailed for at least five years, and most adults could expect a sentence of eight or nine years.

She described the assault as unprovoked violence that was “beyond comprehension”.

“It was not sophisticated in any way. It was just incredibly violent,” she said.

Ms Smith, for the defence, said her client acknowledged the “tragic consequences” of his actions.

She said the teenager grew up in a violent home and that his mother had a drug addiction.

He was undertaking study while in prison and hoped to one day work in a trade.

The teenager, who watched proceedings via videolink from custody, also pleaded guilty to affray, intentionally causing injury, theft, driving unlicensed and possessing a weapon.

He could be sentenced when the case returns to court on July 2.