A 19-year-old man who sexually assaulted a woman and attacked another woman who came to her rescue has received a five year prison sentence.

Glen Reilly of Owensilla, Ballymun, Dublin had pleaded guilty at the Dublin Circuit Criminal Court to sexually assaulting one woman and assaulting another causing her harm in north Dublin on October 12, 2012.

Judge Martin Nolan suspended the last two and a half years of the sentence on condition that he follow the instructions of the Probation Services and be under post release supervision for two years.

The judge said it was ‘mystifying’ as to why Reilly committed such a serious offence “out of the blue” noting his very young age and his lack of previous convictions.

He said that the attack was unprovoked and ‘savage’ and ‘if it wasn’t for the Good Samaritan’ who interrupted Reilly, the victim could have been in a much worse off state.

He noted that Reilly had no memory of the attacks. He said that he suffered a serious brain injury around this time and that he had been drinking on the night.

A probation report had also stated that Reilly was a high risk in relation to sexual offending and violence against women.

At a previous hearing Garda Colm McElligot had told Martina Baxter BL, prosecuting, that both attacks took place shortly before 5am on the date in question.

A mother-of-one had told gardaí she was walking home from a party when she was attacked 50 yards from her own home.

The 30-year-old woman said a boy who had been following her punched her full force in her face, knocking her to the ground.

He punched her face and temples repeatedly, said he had a knife, and put his hand over her mouth, causing her to struggle to breathe. The woman was screaming and in fear of her life.

She said the attacker tried to take off her clothes and his own when a neighbour heard her screams and came to her aid.

The second victim told gardaí she saw a man lying on top of a girl and ran out of her house to pull him off. The man then punched this woman and hit her with a beer can before running away.

Victim impact reports for the two women showed they suffered bruises, cuts and swelling to the face and body. Since the attack they have also experienced stress and anxiety.

When arrested, the teenager said he had taken alcohol and drugs that night and had been assaulted by two men.

Diarmaid McGuinness SC, defending, said the accused suffered a fractured skull, scalp lacerations and bleeding to the brain.

He said his client spent eleven days in Beaumont Hospital and underwent surgery on his face.

Mr McGuinness said doctors were concerned that head injuries could have caused his client's amnesia.

He read out a letter of apology from the teenager saying he was extremely ashamed of his actions.

His father had taken to the stand and offered €1,500 in cash as a gesture of his son's remorse, with a further €3,500 to follow if acceptable.

The court heard that the teenager has attended drugs counselling but has since acquired two minor convictions, one for being drunk in public and the second for failing to appear in court. He had no convictions before the two assaults.