David Wood, 37, ‘met’ the youngster over the internet while she was playing Fortnite on her Xbox.
The girl became infatuated with Wood and was regularly invited to his Washington home where the pair engaged in sexual activity.
Months later, the girl confessed to her mum that she had been involved in a sexual relationship with an older man she had met online.
The girl’s mother said: “It makes me sick to my stomach what he has done.
“My daughter is still a child, my child, and this man has stolen her childhood after grooming her online.
“She should have been out playing with friends, having a laugh and a joke, when in fact she has been preyed on by a man who is more than 20 years older than her.
“He manipulated my daughter. It is disgusting.”
Wood was questioned by police, but he sent a series of messages to his victim urging her to stay quiet.
Initial attempts to bring Wood to justice were thwarted in November last year as the case was dropped in court due to insufficient evidence, and the victim was unwilling to support a prosecution.
He was subsequently jailed for 16 months for perverting the course of justice.
Now, however, Wood has finally admitted two counts of sexual activity with a child and taking indecent photographs of a child at a recent Newcastle Crown Court hearing.
The mother added: “She claimed she was head over heels in love with him but that is what he made her feel.
“The control that he had over her, sending her texts urging her to keep quiet, meant she would not talk to police.
“I’m now incredibly relieved and thankful that David Wood is behind bars. He deserves to be in jail for a long time for the unforgivable things he has done to my daughter and I can sleep easier knowing he is locked up, unable to prey on other vulnerable girls and cause such pain and heartache to their families.”
Wood, of Waterloo Walk, Sulgrave, admitted all three offences on January 16 at Newcastle Crown Court.
He is due to be sentenced on a date to be confirmed.
The girl’s mother added: “I hope this case helps make other parents aware of the potential dangers of the internet. This could so easily happen to other children who come into contact with manipulative adults online.”