Former Ukrainian Prime Minister Yulia Tymoshenko used a pre-trial hearing on Friday to attack President Viktor Yanukovich, alleging he was behind a crooked court action that was certain to convict her of abuse of power.
The case involving Tymoshenko, twice prime minister and now in opposition, has raised concerns by Western governments over Yanukovich's commitment to democracy and the rule of law.
Hemmed in by TV cameraman and journalists in the tiny Kiev courtroom, the 50-year-old political firebrand called on all her oratorical skills as she denounced the hearing as an arranged "farce" and told the judge he was a Yanukovich "puppet".
"At such an important moment for Ukraine, I do not want in that chair a judge like you. I am throwing down this objection to you because I consider you a puppet of the presidential administration," she told judge Rodion Kyreyev.
Kyreyev at times appeared harassed in the face of the verbal barrage from Tymoshenko who has been charged over a 2009 gas supply agreement with Russia when she was prime minister.
But, after deliberating, he subsequently over-ruled Tymoshenko's objection.
However, it was Yanukovich, who defeated her in a bitter fight for the presidency in February 2010, who was the main person in her sights, though.
"The very judicial system which is now in the private hands of Yanukovich and his inner circle does not allow any citizen of Ukraine a chance of justice from the courts," she said.
Outside the court she told reporters: "This mock trial was organised and served up by Viktor Yanukovich.
Nobody has any doubts that the courts and the state prosecution are in private hands and there will be no justice."
Tymoshenko complained of political persecution to the European Court of Human Rights ahead of the trial.
Though Western governments have not come down publicly on her side, diplomats say visiting EU politicians have told the Yanukovich leadership that they are concerned over the possible use of "selective justice" in Ukraine.
With her trademark peasant-style hair braid and combative manner, she is still popular across Ukraine and she brought thousands of supporters out in central Kiev on Friday.
The hearing was called to decide whether to send Tymoshenko for trial for abuse of power over the 2009 gas supply agreement.
The prosecution alleges that she, without consulting her government, forced the then head of Naftogaz to sign the gas deal with Russia's Gazprom.
She denies this.
The agreement ended a stand-off between Russia and its ex-Soviet neighbour over the pricing of Russian gas which had led to supplies being cut off to Western Europe.
It has since been denounced by the Yanukovich leadership as a sell-out, though Kiev is continuing to observe it.
Tymoshenko became known as the "gas princess" in the late 1990s as owner of a company which bought and sold Russian gas.
Since losing to Yanukovich, she has failed to unify the opposition around her.
Supporters who massed in central Kiev carried slogans that read: "We will defend Ukraine ! Down with puppet courts! We are for Yulia, for Ukraine!.
Tetyana Borik, 47, from Poltava, 350 km (220 miles) east of Kiev, said: "I believe that the case against Tymoshenko is political. It is not her who is guilty but (former president Viktor) Yushchenko."
Tymoshenko came to power, serving as prime minister for two terms, following street disturbances called the Orange Revolution in 2004 which doomed Yanukovich's first attempt to secure the presidency.
Yushchenko subsequently became president with Tymoshenko as prime minister but the two fell out over style and policy.
"I am ashamed to live in this country. I want justice. I want to express support for a leader of whom those in power are afraid," said Igor Zakharenko, 50, another Tymoshenko supporter.