Kelvin Singh Jagjit was convicted in August of one charge of aggravated rape and two charges of aggravated sexual assault, according to a report by the Channel News Asia.
The court heard that around midnight on January 13 last year Singh was cycling around Serangoon Gardens armed with a Swiss army knife "looking for victims to rob".
He spotted the 41-year-old victim walking along Kensington Road, having just ended her shift.
The quick-thinking woman flung her handbag containing about 800 Singapore dollars in cash, among other items over a fence into the compound of a private house along the alleyway.
More From This Section
Still holding the knife, Singh forced the victim to remove her clothes and raped her.
The victim then called her boyfriend and told him that she was almost robbed. He then called the police.
Singh was arrested three days later while cycling around the area.
According to a psychiatric report, Singh has "a history of conduct disorder, borderline intelligence...(and) prominent antisocial and narcissistic personality traits", the report said.