Eight of Brazil's presidential candidates � missing imprisoned frontrunner Luiz Inacio Lula da Silva � clashed in the first debate of the campaign Thursday, showcasing sharp

divides in Latin America's biggest nation.

The debate in Sao Paulo, broadcast on TV Bandeirantes, did not feature the four most minor candidates of the 13 who have launched campaigns ahead of the October 7 first round of voting. And Lula's enforced absence due to his corruption conviction cast a shadow, given his stunning lead in the polls.

But four major players were on stage: right-winger Jair Bolsonaro, who is polling in second place after Lula, and his next biggest rivals, center-right former Sao Paulo governor Geraldo Alckmin and environmentalist Marina Silva, followed by leftist Ciro Gomes.

The combative tone among the seven men and one woman quickly illustrated the battle lines after two years of severe recession, a tidal wave of violent crime, and one of the world's biggest corruption scandals.

With deeply unpopular President Michel Temer not seeking a new term, it is the least predictable election in decades.

Alckmin, who wants to be seen as the calm, authoritative, pro-business candidate, stressed the need for market reforms so that the economy can grow and grow strongly.

But Silva scored a point likely to have gone down well with voters angry at the ruling establishment, including Alckmin's center-right PSDB party, when she said:

Those who created the problems won't solve the problems.

Bolsonaro is the candidate getting the most attention other than Lula, who is serving a 12-year sentence for corruption.

However, the former army officer appeared less confident in the live televised debate than he does when he meets his fervent crowds of supporters and spreads his message to a huge social media following.

Asked about the rapidly rising rate of rape and violence against women in Brazil, Bolsonaro repeated his controversial call for voluntary chemical castration of criminals.

I think we would prevent this problem of violence against women, he said.

Guilherme Boulos, of the leftwing Socialism and Liberty Party, used his national TV airtime to tell Bolsonaro: Brazil knows you are racist, macho and homophobic, before going on to accuse him of corruption.

The elephant in the room was Lula.

A court earlier Thursday turned down lawyers' request for Lula to be allowed to participate by video link in the event, arguing it was essential to the campaign.

His leftist Workers' Party also failed to get TV Bandeirantes to mark his absence with an empty chair or to allow his vice presidential pick, former Sao Paulo mayor Fernando Haddad, to take his place.

Instead, party leaders organized what they called an alternative debate in Sao Paulo, which was broadcast on social media, featuring Haddad and other allies.

However surreal it might seem for a jailed ex-president to seek a third term, Lula, who ruled from 2003-2010, means business.

His legal team hopes to persuade the Supreme Electoral Tribunal to allow him to participate, despite the country's clean slate law that would ban anyone having lost an appeal to a criminal conviction � as is Lula's case.

As one of the world's most prominent politicians during his presidency and still a household name in Brazil, Lula boasts the kind of following most other politicians would crave.

That translates into remarkable support, partly based on memories of Lula's trailblazing policies to promote racial and social equality and his stewardship of a commodities-fueled economic boom.

Opinion polls give him around 30 percent in a crowded first round, then winning easily in a second-round runoff.

Lula's fate is only one part of the uncertain electoral picture.

The October polls will also see elections of 27 governors, all 513 congressional lower house deputies and two thirds of the 81 senators.

And so far voters appear hardly enticed by the prospect.

A poll published this month by the National Confederation of Industries showed 45 percent of Brazilians pessimistic or very pessimistic about the elections. While voting is obligatory, a third plan to cast spoiled ballots, the poll found.

Other polls point to between 33 and 41 percent of the electorate defying the law to skip voting.