Ukrainian President Petro Poroshenko, left, and Ukrainian presidential candidate and popular comedian Volodymyr Zelenskiy, right, argue during their debates at the Olympic stadium in Kiev, Ukraine, Friday, April 19, 2019. Friday is the last official day of election canvassing in Ukraine as all presidential candidates and their campaigns will be barred from campaigning on Saturday, the day before the vote.(AP Photo/Vadim Ghirda)

KIEV, Ukraine (AP) — A comedian who is the front-runner in Ukraine's presidential race and the incumbent fighting to retain his job traded accusations in a debate at a sports stadium Friday, just two days before the election.

President Petro Poroshenko, who is trailing in opinion polls ahead of Sunday's presidential runoff, accused his rival, 41-year-old comic actor Volodymyr Zelenskiy, of lacking the political experience needed to keep Ukraine on its pro-Western course and resist Russia's attempts to draw the country back into its orbit.

While Poroshenko charged that his rival lacks a clear program, Zelenskiy shot back, calling the president "a wolf in sheep's clothing."

Zelenskiy, who is widely popular for playing a Ukrainian president fighting corruption in a popular TV sitcom, held the Ukrainian leader responsible for the nation's economic woes and endemic corruption. He insisted that he would continue pushing Ukraine to further integrate into the West.

The debate was watched by some 60,000 people who packed the nation's largest sports arena in Kiev, backing their candidates with enthusiastic chants or booing their opponents.

Zelenskiy tried to put Poroshenko on the defensive, showering the billionaire candy tycoon-turned-president with questions about his business assets and associates of his who have been accused of corruption.

The actor said he voted for Poroshenko five years ago but later realized that "I made a mistake, we made a mistake."

"Could we imagine back then that a new way of life would in fact be a fight for survival?" Zelenskiy said, referring to the country's sharp plunge in living standards since the 2014 vote.

"I'm not a politician, I'm a simple man who has come to break that system," he said, echoing his sitcom character, a schoolteacher suddenly thrust into the presidential seat. "I'm the result of your promises and your mistakes."

Poroshenko shot back, arguing that the actor has failed to spell out his program and pointing at his business ties with self-exiled billionaire tycoon Ihor Kolomoyskyi, the president's archrival.

Poroshenko charged that Zelenskiy's victory would benefit Russia, which annexed Ukraine's Crimean Peninsula in 2014 and has backed separatist rebels in Ukraine's east ever since in fighting that has left 13,000 people dead.

"He would be a weak head of state unable to stand up to (Russian President Vladimir) Putin," Poroshenko said. "An actor can't wage a war against Russia."

Zelenskiy sought to turn the tables on Poroshenko, accusing him of maintaining backdoor channels with the Kremlin and continuing to market his candy in Russia despite the bitter tug-of-war between the two neighbors.

"I will uphold Ukraine's European choice," he insisted.

At some point, both candidates came down to their knees to ask for forgiveness of those who lost their relatives in the five years of fighting in the east.

Prior to the debate, Poroshenko rallied thousands of his supporters at the capital's Independence Square, which was the heart of Ukraine's 2014 opposition protests that ousted the nation's former Russia-friendly president.

Lyudmila Soloveyko, a 56-year-old schoolteacher who went to the rally, said she's grateful to Poroshenko for "opening the door to Europe for Ukrainians," referring to the EU decision to scrap visas for traveling Ukrainians, which Poroshenko had lobbied for.

Zelenskiy has avoided a traditional political campaign, touring the country with his comedy show instead. In his rare interviews, he has pledged to continue the push for close ties with the EU and NATO but also spoke out for more active efforts to reintegrate the rebels in the east back into Ukraine's fold.

Zelenskiy's supporters scoffed at the president's claim that the actor would be easy prey for the Kremlin and pointed at the economic woes and corruption during Poroshenko's time at the helm.

"We have got tired of the old politicians who are good at nothing but talk," said 54-year-old sales clerk Yevgenia Ostroshitskaya. "Life only has been getting worse. Let Zelenskiy give it a try, he has done it well in the movies."

Zelenskiy won 30% of the vote in the March 31 first round vote while Poroshenko got 16%, and the gap has widened as Sunday's runoff has approached.

A poll released Thursday by the Rating agency suggested Zelenskiy has 58% support, while Poroshenko has just 22%. The poll of 3,000 people had a margin of error of 1.8 percentage points.

Ukrainian President Petro Poroshenko, left, and Ukrainian presidential candidate and popular comedian Volodymyr Zelenskiy, right, argue their debates at the Olympic stadium in Kiev, Ukraine, Friday, April 19, 2019. Friday is the last official day of election canvassing in Ukraine as all presidential candidates and their campaigns will be barred from campaigning on Saturday, the day before the vote.(AP Photo/Vadim Ghirda)
People wait for the start of debates between two candidates in the weekend presidential run-off at the Olympic stadium in Kiev, Ukraine, Friday, April 19, 2019. Friday is the last official day of election canvassing in Ukraine as all presidential candidates and their campaigns will be barred from campaigning on Saturday, the day before the vote. (AP Photo/Vadim Ghirda)
People hold Ukrainian national flag at the Olympic stadium prior debates between two candidates in the weekend presidential run-off in Kiev, Ukraine, Friday, April 19, 2019. Friday is the last official day of election canvassing in Ukraine as all presidential candidates and their campaigns will be barred from campaigning on Saturday, the day before the vote. (AP Photo/Efrem Lukatsky)
Supporters of Ukrainian President Petro Poroshenko gather to march to the Olympic stadium ahead of debates between two candidates in the weekend presidential run-off in Kiev, Ukraine, Friday, April 19, 2019. Friday is the last official day of election canvassing in Ukraine as all presidential candidates and their campaigns will be barred from campaigning on Saturday, the day before the vote. (AP Photo/Vadim Ghirda)
Supporters of Ukrainian President Petro Poroshenko listen to him as they gather to march to the Olympic stadium ahead of debates between two candidates in the weekend presidential run-off in Kiev, Ukraine, Friday, April 19, 2019. Friday is the last official day of election canvassing in Ukraine as all presidential candidates and their campaigns will be barred from campaigning on Saturday, the day before the vote. (Mykola Lazarenko, Ukrainian Presidential Press Service via AP)
A man holds an Ukrainian flag as protesters gather to march to the Olympic stadium ahead of debates between two candidates in the weekend presidential run-off in Kiev, Ukraine, Friday, April 19, 2019. Friday is the last official day of election canvassing in Ukraine as all presidential candidates and their campaigns will be barred from campaigning on Saturday, the day before the vote. (AP Photo/Vadim Ghirda)
Ukrainian President Petro Poroshenko speaks to his supporters as protesters gather to march to the Olympic stadium ahead of debates between two candidates in the weekend presidential run-off in Kiev, Ukraine, Friday, April 19, 2019. Friday is the last official day of election canvassing in Ukraine as all presidential candidates and their campaigns will be barred from campaigning on Saturday, the day before the vote. (AP Photo/Vadim Ghirda)
Women applaud as protesters gather to march to the Olympic stadium ahead of debates between two candidates in the weekend presidential run-off in Kiev, Ukraine, Friday, April 19, 2019. Friday is the last official day of election canvassing in Ukraine as all presidential candidates and their campaigns will be barred from campaigning on Saturday, the day before the vote. (AP Photo/Vadim Ghirda)
A woman holds an Ukrainian flag as protesters gather to march to the Olympic stadium ahead of debates between two candidates in the weekend presidential run-off in Kiev, Ukraine, Friday, April 19, 2019. Friday is the last official day of election canvassing in Ukraine as all presidential candidates and their campaigns will be barred from campaigning on Saturday, the day before the vote. (AP Photo/Vadim Ghirda)
Ukrainian President Petro Poroshenko, center, greets his supporters as they gather to march to the Olympic stadium ahead of debates between two candidates in the weekend presidential run-off in Kiev, Ukraine, Friday, April 19, 2019. Friday is the last official day of election canvassing in Ukraine as all presidential candidates and their campaigns will be barred from campaigning on Saturday, the day before the vote. (AP Photo/Vadim Ghirda)
Supporters of Ukrainian President Petro Poroshenko march to the Olympic stadium ahead of debates between two candidates in the weekend presidential run-off in Kiev, Ukraine, Friday, April 19, 2019. Friday is the last official day of election canvassing in Ukraine as all presidential candidates and their campaigns will be barred from campaigning on Saturday, the day before the vote. (AP Photo/Vadim Ghirda)
Supporters of Ukrainian President Petro Poroshenko march to the Olympic stadium ahead of debates between two candidates in the weekend presidential run-off in Kiev, Ukraine, Friday, April 19, 2019. Friday is the last official day of election canvassing in Ukraine as all presidential candidates and their campaigns will be barred from campaigning on Saturday, the day before the vote. (AP Photo/Vadim Ghirda)
Ukrainian riot police stand ready at the Olympic stadium ahead of debates between the two candidates in the weekend presidential run-off in Kiev, Ukraine, Friday, April 19, 2019. Friday is the last official day of election canvassing in Ukraine as all presidential candidates and their campaigns will be barred from campaigning on Saturday, the day before the vote. (AP Photo/Vadim Ghirda)
Volodymyr Zelenskiy, Ukrainian actor and candidate gestures as he attends debates between two candidates in the weekend presidential run-off at the Olympic stadium in Kiev, Ukraine, Friday, April 19, 2019. Friday is the last official day of election canvassing in Ukraine as all presidential candidates and their campaigns will be barred from campaigning on Saturday, the day before the vote. (AP Photo/Vadim Ghirda)
People react during debates between Ukrainian President Petro Poroshenko and Ukrainian presidential candidate and popular comedian Volodymyr Zelenskiy at the Olympic stadium in Kiev, Ukraine, Friday, April 19, 2019. Friday is the last official day of election canvassing in Ukraine as all presidential candidates and their campaigns will be barred from campaigning on Saturday, the day before the vote. The banner reads
Presidential candidates, Ukrainian President Petro Poroshenko, left, and popular comedian Volodymyr Zelenskiy attend debates in the weekend presidential run-off at the Olympic stadium in Kiev, Ukraine, Friday, April 19, 2019. A comedian leading Ukraine’s presidential race and the incumbent faced off in a debate at the nation’s largest sports arena Friday, fiercely trading accusations two days before the runoff. (AP Photo/Efrem Lukatsky)
People react during debates between two candidates in the weekend presidential run-off at the Olympic stadium in Kiev, Ukraine, Friday, April 19, 2019. Friday is the last official day of election canvassing in Ukraine as all presidential candidates and their campaigns will be barred from campaigning on Saturday, the day before the vote. (AP Photo/Vadim Ghirda)
Spectators cheer during debates between Ukrainian President Petro Poroshenko and Ukrainian presidential candidate and popular comedian Volodymyr Zelenskiy at the Olympic stadium in Kiev, Ukraine, Friday, April 19, 2019. Friday is the last official day of election canvassing in Ukraine as all presidential candidates and their campaigns will be barred from campaigning on Saturday, the day before the vote. (AP Photo/Sergei Grits)
Police officers stay guard during debates between Ukrainian President Petro Poroshenko and Ukrainian presidential candidate and popular comedian Volodymyr Zelenskiy at the Olympic stadium in Kiev, Ukraine, Friday, April 19, 2019. Friday is the last official day of election canvassing in Ukraine as all presidential candidates and their campaigns will be barred from campaigning on Saturday, the day before the vote. (AP Photo/Sergei Grits)
Ukrainian President Petro Poroshenko, left, and Ukrainian presidential candidate and popular comedian Volodymyr Zelenskiy, right, attend their debates at the Olympic stadium in Kiev, Ukraine, Friday, April 19, 2019. Friday is the last official day of election canvassing in Ukraine as all presidential candidates and their campaigns will be barred from campaigning on Saturday, the day before the vote. (AP Photo/Sergei Grits)
People react during debates between two candidates in the weekend presidential run-off at the Olympic stadium in Kiev, Ukraine, Friday, April 19, 2019. Friday is the last official day of election canvassing in Ukraine as all presidential candidates and their campaigns will be barred from campaigning on Saturday, the day before the vote. (AP Photo/Vadim Ghirda)
Ukrainian President Petro Poroshenko, third left, and Ukrainian presidential candidate and popular comedian Volodymyr Zelenskiy, third right, sing the national anthem after their debates at the Olympic stadium in Kiev, Ukraine, Friday, April 19, 2019. Friday is the last official day of election canvassing in Ukraine as all presidential candidates and their campaigns will be barred from campaigning on Saturday, the day before the vote.(AP Photo/Vadim Ghirda)
Volodymyr Zelenskiy, Ukrainian actor and candidate gestures as he attends debates between two candidates in the weekend presidential run-off at the Olympic stadium in Kiev, Ukraine, Friday, April 19, 2019. Friday is the last official day of election canvassing in Ukraine as all presidential candidates and their campaigns will be barred from campaigning on Saturday, the day before the vote. (AP Photo/Vadim Ghirda)
Ukrainian President Petro Poroshenko, left, and Ukrainian presidential candidate and popular comedian Volodymyr Zelenskiy, right, attend their debates at the Olympic stadium in Kiev, Ukraine, Friday, April 19, 2019. Friday is the last official day of election canvassing in Ukraine as all presidential candidates and their campaigns will be barred from campaigning on Saturday, the day before the vote.(AP Photo/Vadim Ghirda)
Ukrainian President Petro Poroshenko, left, and Ukrainian presidential candidate and popular comedian Volodymyr Zelenskiy, right, attend their debates at the Olympic stadium in Kiev, Ukraine, Friday, April 19, 2019. Friday is the last official day of election canvassing in Ukraine as all presidential candidates and their campaigns will be barred from campaigning on Saturday, the day before the vote. (AP Photo/Sergei Grits)
Ukrainian President Petro Poroshenko, left, and his wife Maryna arrive to attend debates between two candidates in the weekend presidential run-off at the Olympic stadium in Kiev, Ukraine, Friday, April 19, 2019. Friday is the last official day of election canvassing in Ukraine as all presidential candidates and their campaigns will be barred from campaigning on Saturday, the day before the vote. (AP Photo/Efrem Lukatsky)
Policemen stand at the Olympic stadium prior debates between two candidates in the weekend presidential run-off in Kiev, Ukraine, Friday, April 19, 2019. Friday is the last official day of election canvassing in Ukraine as all presidential candidates and their campaigns will be barred from campaigning on Saturday, the day before the vote. (AP Photo/Efrem Lukatsky)