KIEV, Ukraine — The Ukrainian presidential race took a surreal turn on Sunday when what was supposed to be a debate between the two candidates featured President Petro O. Poroshenko discussing Ukraine’s future with an empty lectern bearing the name of his rival, a comedian.
His rival, Volodymyr Zelensky, had made clear beforehand that he would not attend the debate because of a quarrel over timing. But the president, struggling to revive his flagging re-election campaign, went ahead anyway, assailing his opponent as an unserious “virtual candidate.”
The one-man “debate,” held in a stadium complex in Kiev, the capital, and broadcast live on television, came just a week before the second and decisive round of an election that has been dominated from the start by theatrical stunts and dirty tricks rather than policy issues like how to settle a five-year-old war in the east of the country.
Mr. Poroshenko, speaking with journalists invited to the event, seized on Mr. Zelensky’s absence to press his campaign pitch that voters should not trust Ukraine’s future to an untested comic at a time of war. Mr. Zelensky has never held office, and has no political experience — aside from a television role in which his character, a teacher, accidentally becomes president.
“I don’t like it when instead of participating in debate we have a virtual candidate who wants to convince us only through videos,” Mr. Poroshenko, a 53-year-old candy tycoon, said of Mr. Zelensky, 41.“It is not worthy of Ukrainian democracy.”
Noting that the president commands the armed forces and does not hold just a ceremonial position, he derided Mr. Zelensky, saying he was treating the election like “a plot from the movies.”
Hundreds of the president’s supporters gathered outside the stadium, waving Ukrainian flags and cheering his mocking of Mr. Zelensky, who has said he is ready to debate, but not until Friday. The runoff election is on Sunday.
Mr. Poroshenko, who was elected after street protests in 2014 toppled Ukraine’s deeply corrupt leader, Viktor F. Yanukovych, has struggled to win over voters, besieged by accusations of corruption from some of his close friends and political allies.
Many Ukrainians are angry and disappointed over the dashing of hopes raised by their country’s so-called Revolution of Dignity in 2014. This has made it difficult for Mr. Poroshenko to win traction for his argument that electing Mr. Zelensky would play into the hands of President Vladimir V. Putin of Russia.
In the first round of voting in late March, Mr. Zelensky won far more votes than Mr. Poroshenko and more than 30 other candidates. Since then, opinion polls have shown him far ahead of the president.