Ukrainian leader Petro Poroshenko has agreed to meet outsider and comic Volodymyr Zelenskiy in a face-to-face debate in the capital’s Olympic stadium on April 5 in what may turn out to be a presidential elections disaster for the challenger.

Poroshenko threw down the gauntlet earlier this week and Zelenskiy accepted but imposed a series of conditions, including that the debate had to be held in the stadium, that both candidates had to submit to an alcohol and drug test and that all press were given access and the right to broadcast the challenge. Zelenskiy also invited opposition leader and runner-up in the recent first round of the elections Yulia Tymoshenko to moderate the debate.

Poroshenko accepted all the conditions. At the time of writing Ukrainian social media was abuzz as the two candidates arrived at the medical testing stations to give up blood samples.

Agreeing to go on stage with Poroshenko may turn out to be a mistake for Zelenskiy. With many years behind him in office, having served as a minister in two previous governments before becoming president, Poroshenko is a strong public orator who can speak for hours on complicated policy issues without notes, whereas Zelenskiy is brand new to the game, but is of course a confident performer.

What started off as grandstanding by Zelenskiy, who has released a series of slick videos in the last two days playing up the debate, may go wrong if Poroshenko can force him into a serious discussion on substantive issues while the whole country is watching.

Zelenskiy has successfully sullied Poroshenko by saying little on policy so far and intends to rely on expert help if he were to win the second round vote on April 21. Poroshenko, on the other hand, has played the nationalist card and sold himself as the only reliable candidate who can face down Russian aggression. The two issues that the electorate care most about is improving the crushed standard of living and dealing with the war in the eastern regions.

Observers say Ukraine's two-round election is one of the country's most unpredictable votes since it gained independence from the Soviet Union in 1991. Some 39 candidates stood in the first round of the elections.

The two candidates have taken to social media to spar in the run-up to the debate.

“…let it be a stadium”
"(If you want) a stadium, let it be a stadium," Poroshenko said in a video address.

The president warned that an election debate was no laughing matter and a presidential election would determine the country's fate for decades to come.

"A debate is not a show," Poroshenko said in an apparent jab at Zelenskiy's lack of political experience. "A debate is not staged for a stadium spectacle."

Zelenskiy accepted a debate with Poroshenko after a viral campaign on social media urging him to publicly share his political opinions and proposals, about which he has said little so far.

Among the other conditions that Zelenskiy insisted on was that Poroshenko should stop calling him a "clown" and a "puppet," a reference to the frontrunner's alleged political ties to oligarch Igor Kolomoisky.

The country is transfixed by the spectacle, which is totally out of keeping with Ukraine’s normal post-Soviet routine with elites playing the populist card or bribing the electorate with cheap gas and increased pensions.

"It looks like the debates at the Olympic Stadium will become a political duel whose result will show whether the incumbent will be able to reverse the course of the campaign," tweeted Ukrainian lawmaker Mustafa Nayyem.