The man accused of murdering schoolgirl Lucy McHugh told a court her claims he had got her pregnant were “nonsense”.
Lucy, 13, was found stabbed to death in woodland at Southampton Outdoor Sports Centre in July 2018.
Stephen Nicholson told jurors the teenager said she would tell her mum she was carrying his child as she was “trying to cause trouble”.
Mr Nicholson, 25 denies the murder and rape of Lucy and a series of sexual offences against Lucy and another girl.
The jury at Winchester Crown Court had previously been told there is no evidence that Lucy was or ever had been pregnant.
Mr Nicholson began lodging at the Southampton house where Lucy and her family lived in 2017, the court was told.
Giving evidence, Mr Nicholson said he received a message on Facebook from Lucy the night before her death, saying she would tell her mother he had got her pregnant unless he met her at a nearby park.
“She was just making stuff up, trying to cause trouble – it was nonsense,” he told the court.
He said he responded by saying “yeah whatever” before deleting and blocking her.
Mr Nicholson told the court did not get on with Lucy.
He said he had blocked multiple attempts by her to add him on Snapchat and he did “not see eye-to-eye” with the girl.
His belongings would go missing and his clothes had been found in Lucy’s room, he said.
“She would follow me around the house, always trying to get in my way and get involved with stuff that wasn’t anything to do with her,” he told jurors.
He said on one morning in March 2018, Lucy had tried to push him down a flight of stairs and he subsequently sent a string of angry text messages to her mother.
These included him saying he would “pay a bunch of girls at Lucy’s school to beat her up”, jurors were told.
Asked by defence barrister James Newton-Price QC why he sent the messages, Mr Nicholson said he had been “angry” and was “venting”.
He told the court he had been unaware of notes written by Lucy and conversations with her friends in which she described him as her “boyfriend”.
“It was nonsense,” he said.
The court was shown CCTV footage of a cyclist at the sports centre on the day Lucy went missing.
But Mr Nicholson said it was not him and the person in the footage was wearing different grey trainers to his.
Mr Newton-Price asked the defendant how bloodstained clothes allegedly dumped in woodland at Tanner’s Brook came to contain his and Lucy’s DNA.
“I do not know,” replied Mr Nicholson.
He said he had been there on the day Lucy went missing but only to meet a man, whose identity he did not know, to sell cannabis.
The court heard Mr Nicholson’s mobile phone internet history showed he later searched for “what time can you start a bonfire in Southampton?”.
This was because he was planning to burn some belongings from his shed he no longer needed and “wanted to make sure it was all above board”, he told the court.
He said he burned a number of items that day, including the trainers he was wearing.
Concluding his questioning, Mr Newton-Price asked: “Did you ever have a sexual relationship with Lucy McHugh?”
“No,” Mr Nicholson replied.
“Did you kill Lucy McHugh?” asked Mr Newton-Price. Mr Nicholson responded: “No.”
Earlier, the judge directed the jury to return a not guilty verdict on one count of sexual activity with a child after the prosecution decided it had insufficient evidence.
Care worker Mr Nicholson, formerly of Mansel Road East, Southampton, denies murder, three charges of raping Lucy when she was 12 and one count of sexual activity with a child once she had turned 13.
He also denies a count of sexual activity with a 14-year-old girl in 2012.
The trial continues.