Coleen Rooney "pointed the finger" at Rebekah Vardy as "the villain" who leaked stories to the press about her private life, the High Court has heard.
The wife of ex-England footballer Wayne Rooney was dubbed "Wagatha Christie" for her "sting operation" involving posting false stories on Instagram which later appeared in The Sun.
Mrs Rooney then said the source of those leaks was the account of Mrs Vardy.
She is suing Mrs Rooney for libel.
Mrs Vardy, 38, was accused by Mrs Rooney of leaking stories over the course of five months. She denies the accusation.
At the High Court, Mrs Vardy's barrister Hugh Tomlinson QC said Mrs Rooney's posts were an "untrue and unjustified defamatory attack... published and republished to millions of people".
He said the spat had been trivialised in the media as "wag wars" but "the impact on Mrs Vardy was not trivial".
Last year Mrs Rooney said she planted three false stories on her Instagram stories and blocked all users except for Mrs Vardy's account.
Court documents say the three fake stories that appeared in The Sun consisted of Mrs Rooney travelling to Mexico to "see what this gender selection is all about", returning to TV, and the basement flooding in her house.
On a Twitter post, she wrote: "I have saved and screenshotted all the original stories which clearly show just one person has viewed them.
"It's ................ Rebekah Vardy's account."
Mr Tomlinson said Mrs Rooney's social media post made it clear that the person accused of leaking the stories "is Rebekah Vardy, the finger is being pointed at her, as the villain, the person, the someone, the one person".
The Twitter backlash led some social media users to link Mrs Vardy with "the disappearance of Madeline McCann", and joke she was the new leader of the so-called Islamic State group, the barrister added.
Mr Tomlinson wrote that the accusations had made Mrs Vardy feel suicidal, she had taken three trips to the hospital due to anxiety, and had fears she would lose her baby due to the stress of the situation.
The written statement claims Mrs Vardy's footballer husband Jamie has also been the subject of ridicule, with opposition supporters shouting taunting chants such as "Becky Vardy's a grass".
Mrs Rooney's legal team claims Mrs Vardy "was in fact responsible for consistently passing on information about the defendant's private Instagram posts and stories to The Sun".
David Sherbourne, representing Mrs Rooney, stated in written submissions the message readers would take away from Mrs Rooney's tweet was "it was Rebekah Vardy's account that was the source of private stories about the defendant appearing in The Sun - not Rebekah Vardy herself".
He added: "The fact that these sting operation stories also then appeared in The Sun... is the reason why the defendant published the post which is the subject of this claim."
Mr Tomlinson said both Mrs Vardy and Mrs Rooney had agreed for a "stay" of proceedings until February, so there could be "one final attempt to resolve the matter without the need for a full trial".
Neither Mrs Rooney nor Mrs Vardy attended the preliminary hearing in London.
At the hearing, Mr Justice Warby was asked to determine the "natural and ordinary" meaning of Mrs Rooney's posts.
The judge said he would give his ruling on Friday afternoon.