The 48-year-old woman was attacked from behind while walking to work in Chisholm in the early hours of February 17 last year.

She was beaten and raped before the attacker left with her handbag and mobile phone.

Her attacker, who cannot be named because he was 17 at the time of the offence, appeared in the ACT Supreme Court for sentencing yesterday, after pleading guilty last month to sexual assault in the first degree, two counts of sexual intercourse without consent, and theft.

The court heard he punched the woman in the face and told her to shut up when she screamed.

He forced her to the ground and raped her and walked away before returning for her bag.

He then took the victim's handbag home and showed it to his aunt, and suggested she try using the bankcards.

He told his aunt he had snatched the bag from a woman in the street.

His aunt then tried unsuccessfully to use the victim's credit card, which ultimately led police to arrest the teenager two days after the attack.

He pleaded not guilty to the assault but changed his plea before the trial set down for later this month.

A case worker from Bimberi Youth Justice Centre told the court yesterday the teenager had a childhood marred by abuse and displacement, and a chronic alcohol problem.

She said the teenager, who has no prior convictions and no history of violence, had not finished Year 10, and had a reading level six years below his age.

She said he had refused to talk about the assault in detention, saying it made him feel sick to be reminded of what he had done.

His barrister, James Sabharwal, said the teenager had been drinking before the assault, and that he had consumed half a case of rum and Coke cans before going to a park to sober up.

He said the teen had been speaking with his friend about traumatic events in his childhood, and had become angry, taking his rage out on the victim, a stranger who was in the wrong place at the wrong time.