A Grassmere man has been jailed for five years after pleading guilty to raping a sleeping woman in his bed.

Tristan Quarrell, 22, pleaded guilty in the Warrnambool County Court mid last week to one count of rape.

On Wednesday Judge Claire Quin imprisoned Quarrell for five years and ordered he serve a non-parole period of two years and six months.

He has already served six days in jail.

Judge Quin said registration on the sex offenders registry was not mandatory and she decided not to register Quarrell.

She said Quarrell knew the victim was struggling after a relationship break-up, the woman had accompanied him to his home and was sleeping in his bed.

Quarrell got in the bed, pulled her tracksuit pants down and raped the woman while she slept.

The victim had a dream-like recollection of the incident and the next morning asked Quarrell if he had sex with her, which he admitted.

Judge Quin said Quarrell then went to police and admitted his offending before a report was made.

The next day the woman made a statement to police and made a recorded phone call to Quarrell, who again admitted his actions and apologised.

In a victim impact statement the woman said the offending was a nightmare and she now had problem trusting others, including her friends.

She said she did not like being touched intimately, at one time she had broken down crying and she just wanted to feel safe and "normal" again, which she said may never happen.

Judge Quin said Quarrell's parents had battled substance abuse, but his grandparents had provided consistent and unwavering support and care.

He has no prior court appearances and attempted suicide since the offending.

The judge said Quarrell has participated in the Gunditjmara family violence program, the victim was not required to give evidence at court and the defendant had not sought to blame her in any way.

He had in fact expressed genuine remorse about the impact of his offending and had other people check on her before the matter was even reported to police, she said.

Judge Quin said the case was dependent on Quarrell's admissions as the victim had limited recollection of the incident and the case would not have succeeded without his involvement.

"You provided all the evidence to convict you," she said during sentencing.

The judge said Quarrell had excellent prospects for rehabilitation and she hoped it was his first and last contact with the criminal justice system.

But, she added that rape was a serious crime, although the case lacked a lot of the aggravating factors of other rape offences.

The judge said the offence lasted seconds and there was no physical trauma or violence or weapons.

"However, the impact has been significant. Rape is an intensely personal crime," she said.

"You took advantage of a vulnerable woman as she slept. Only a term of imprisonment is appropriate."

Call Lifeline 13 11 14.

Last week: A 19-year-old woman raped in her sleep says she fears she will never feel safe again.

The woman's victim impact statement was heard during the plea hearing of Tristan Quarrell, 22, in Warrnambool County Court on Wednesday.

The Grassmere man pleaded guilty to a single count of rape.

Prosecutor Stephen Devlin said the man and woman, who were known to each other, caught up on March 6.

He said the woman was struggling to cope emotionally after a break-up and the pair went for a walk before attending his house later that night.

Mr Devlin said they stayed up talking until about midnight when the victim went to bed and fell asleep.

He said the man joined and on three occasions he cuddled the victim, became sexually aroused and rolled away.

On the fourth occasion Quarrell raped the teenager while she was sleeping.

The court heard the victim had a dream-like recollection the following day and messaged Quarrell, who then contacted a female friend and explained what he did.

Quarrell attended a south-west police station on March 7 and reported his offending.

Mr Devlin said in a recorded phone conversation the man apologised to the victim, said he didn't know why he did it and offered to pay for therapy.

The victim has since suffered nightmares and struggles socially and emotionally, she wrote in a victim impact statement.

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She said she also struggled to find motivation to look after herself and when she was alone she constantly checked if the offender was around.

"I just want to feel safe and normal again," the victim wrote.

"I'm starting to think that may never be possible."

A family member of the offender told the court she didn't agree with what Quarrell did but she believed he went "out of his way to do the right thing" after the offending occurred.

A lawyer for Quarrell said the man experienced a deprived childhood and suffered ADHD and depressive symptoms.

She said on the night before the offending the man hadn't slept after drinking alcohol and consuming a gram of cocaine at a concert.

The lawyer said her client's prospects of rehabilitation should be seen as strong given his evidence of remorse, lack of prior criminal history and age.

The man was taken into custody and will be sentenced on October 12.

The charge of rape carries a maximum penalty of 25 years' jail and a standard sentence of 10 years.

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