A man discovered a violent sex predator attacking his hysterical partner in an Alexandria street.
Steven Shillan pounced on the 34 year-old stranger as she walked in May this year.
The 21 year-old, from Burns Street in the town, told his victim: “I am going to rape you.”
The High Court in Glasgow heard how the woman’s boyfriend happened to be nearby and spotted what was happening.
Prosecutor Mark McGuire said: “He shouted: ‘Get off her. What the f*** are you doing?’.”
Shillan – who works as a groundskeeper – then got up and fled the scene.
However, he was later snared after the woman’s blood was on his denims and trainers.
Shillan is now behind bars after he pled guilty to a charge of sexually assaulting the victim with intent to rape last week.
He will be sentenced next month.
The court heard how Shillan grabbed the woman as she walked near Alexandria’s Argyll Estate.
He put his arm around her neck before punching and kicking her as well as stamping on her face.
Mr McGuire said the force was such his footprint was “clearly visible”.
The hearing was told the victim was left in “no doubt” what Shillan planned.
The bleeding woman yelled and tried to stop Shillan from sexually assaulting her.
The terrifying attack only ended when her partner luckily arrived.
The woman was described as “hysterical” with her face covered in blood.
She was later treated for bruising and swelling, but fortunately suffered no fractures.
Mr McGuire: “The attack has had a profound and continuing effect on her.”
Shillan, also of Alexandria, was recognised from CCTV footage from around the area at the time.
He made no comment when held – but forensic evidence later pinned him to the attack.
Lord Boyd remanded him in custody as sentencing was deferred for reports.
