"There is one reason why we are here today -- the results of the elections on 21 November were stolen," Yushchenko said. "More than 3 million votes were stolen were stolen by my opponent, by his team."
Yushchenko said the falsification had been "total," especially in the eastern regions of the country. The Supreme Court annulled the vote -- which was won by Yanukovych -- due to electoral fraud.
Yushchenko said the Ukrainian people had "won their freedom, their right to live in a free and democratic country."
Yushchenko chided Yanukovych, saying electoral laws are not the only guidelines that condemn "stealing."
"You [Yanukovych] are a religious person, correct?" Yushchenko asked. "Thou shalt not steal. Thou shalt not steal things. Thou shalt not steal factories. Thou shalt not steal votes."
Yushchenko accused Russia, which has backed Yanukovych, of interfering in Ukrainian politics. He said foreign intervention -- either from Russia or from the West -- is "humiliating to independent Ukraine."
Yanukovych spoke frequently in Russian, widely heard in the eastern areas of Ukraine seen as backing his candidacy. He said Yushchenko had been supported by the United States and other Western countries.
He said a Yushchenko victory could divide the country, and called for whoever wins to form a national unity government.
"Viktor Andreyevich [Yushchenko], you think that you will win and become president of Ukraine," Yanukovych said. "You are making a huge mistake. You will be president of part of Ukraine. I don't want this. I want us both to unite Ukraine."
Yanukovych said he is "struggling" not for power, but to avoid "bloodshed."
He also offered an apology for what he called "improprieties" in the election campaign.
"I want to apologize to all of you that there were some improprieties in this election campaign," Yanukovych said. "I want us to have no bad will after this election."
Yanukovych said the pro-democracy protests -- dubbed the "Orange Revolution" -- amounted to a coup, and he accused outgoing President Leonid Kuchma of supporting the movement.
The two candidates were allowed to ask each other direct questions after their opening statements during the 100-minute debate. Yushchenko's questions focused on economic matters, pensions, the budget, and salaries. Yanukovych emphasized improvements to Ukraine's economy while he was prime minister.
The debate was marked by several sharp exchanges and finger-pointing, but the two shook hands cordially when it ended.
It marked the first time the pair had come face to face since doctors confirmed that Yushchenko was deliberately poisoned with dioxin during the campaign. Two investigations are under way in Ukraine into the case. The poisoning was not mentioned during the debate.
Also yesterday, Russian President Vladimir Putin and German Chancellor Gerhard Schroeder agreed to respect the result of the Ukrainian election.
The European Union said today that it is not taking sides in the election, but wants a "free and fair" vote.
For more RFE/RL coverage and analysis of the political crisis in Ukraine, click here.