Russian billionaire Roman Abramovich, the owner of Chelsea football club, won his bitter legal battle with fellow oligarch Boris Berezovsky in a British court on Friday.
Berezovsky, 66, was seeking more than £3 billion ($4.75 billion, 3.8 billion euros) in damages from Abramovich after accusing the 45-year-old of blackmail, breach of trust and breach of contract.
But Judge Elizabeth Gloster ruled in Abramovich's favour at London's High Court after a four-month trial and described Berezovsky as an "unimpressive and inherently unreliable witness".
Berezovsky claimed Abramovich had "betrayed" him and "intimidated" him into selling shares in the Russian oil company Sibneft for a "mere 1.3 billion dollars". Abramovich firmly denied the allegations.
The judge said the case boiled down to "whether to believe Berezovsky or Abramovich".
Because the allegations "depended so very heavily on the oral evidence of Mr Berezovsky, the court needed to have a high degree of confidence in the quality of his evidence", she said.
"That meant confidence not only in his ability to recollect things accurately, but also in his objectivity and truthfulness as a witness."
In a lengthy judgement, she added: "On my analysis of the entirety of the 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 that "on occasions he tried to avoid answering questions by making long and irrelevant speeches, or by professing to have forgotten facts which he had been happy to record in his pleadings or witness statements".
Speaking outside court, Berezovsky said he was "absolutely amazed" by the ruling, which he claimed could have been written by Russian President Vladimir Putin, his arch-enemy.
"Lady Gloster took responsibility to rewrite Russian history," Berezovsky said.
"I don't understand. Sometimes I have the impression that Putin himself wrote this judgement."
Abramovich said in a statement that his belief that there had been no merit in Berezovsky's allegations had been "comprehensively vindicated by the court".
In a brief comment on the judgement, Putin's press secretary Dmitry Peskov said it was "always pleasant when slander is called by its true name".
Abramovich and Berezovsky spent a reported total of 100 million pounds fighting the case, which has involved an army of lawyers.
The trial shone a spotlight on the lavish lifestyles of the oligarchs, and the political influence that Berezovsky wielded when Boris Yeltsin was Russian president in the 1990s.
Abramovich told the court that Berezovsky was paid millions of pounds for his services as a "political godfather" but was not a business partner of his.
Berezovsky fled Russia in 2000 after he fell out with Putin during his first term as president.
He enjoyed a reputation as being the power behind the Kremlin throne when Yeltsin, in failing health, was forced to frequently remove himself from daily affairs and hand key decisions to advisors.
Berezovsky once claimed credit for the idea of picking Putin as Yeltsin's chosen successor before admitting that the plan backfired when the new Russian leader surrounded himself with more trusted agents instead.
The so-called Kremlin "family" that clustered around Yeltsin at the time included Berezovsky and the president's daughter as well as several other tycoons who were cast out once Putin rose to power.
London-based Abramovich bought Chelsea in 2003 and has pumped hundreds of million pounds into the club, who became European champions in May this year.