Chelsea Football Club owner Roman Abramovich said he had been "comprehensively vindicated" after winning a High Court battle with Russian oligarch Boris Berezovsky and being described by a judge as truthful and reliable.
Mrs Justice Gloster dismissed a series of claims by Mr Berezovsky - who wanted more than £3 billion damages - and said Mr Abramovich had been a meticulous, responsible, careful and thoughtful witness.
She rejected Mr Berezovsky's allegations that Mr Abramovich had been "dishonest and cynical" and had manipulated a trial thought to have costs tens of millions of pounds in legal fees.
The judge said Mr Berezovsky had been an "unimpressive, and inherently unreliable, witness" and had, at times, given evidence which was "deliberately dishonest" and "incredible".
Mr Berezovsky, 66, sued and accused Mr Abramovich, 45, of blackmail, breach of trust and breach of contract. He said the billionaire Russian businessman had "intimidated" him into selling shares in a Russian oil company at a fraction of their value and broken a promise made during a deal relating to a Russian aluminium company.
Mr Abramovich said the claims had "no merit".
Mrs Justice Gloster ruled in Mr Abramovich's favour following a trial - staged in London between October 2011 and January - at which both men gave evidence.
"I found Mr Berezovsky an unimpressive, and inherently unreliable, witness, who regarded truth as a transitory, flexible concept, which could be moulded to suit his current purposes," she said, at a hearing in London.
"I regret to say that the bottom line of my analysis of Mr Berezovsky's credibility is that he would have said almost anything to support his case."
She said she rejected Mr Berezovsky's claims "in their entirety".