SAO PAULO (Reuters) - Fernando Haddad, the presidential candidate for Brazil’s leftist Workers Party (PT), is closing the gap with poll-leading far-right candidate Jair Bolsonaro for an Oct. 7 first-round vote and would beat him in a runoff, a survey released Monday showed.

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Bolsonaro held steady at 28 percent of voter approval in the first round as compared to the same Ibope poll released last week. Haddad gained three percentage points to hit 22 percent, according to the survey, released by the Estado de S.Paulo newspaper and the Globo TV network.

In the likely scenario of a runoff vote, required by law if no candidate wins a majority in the first ballot, Haddad has 43 percent compared to Bolsonaro’s 37 percent. Last week, Ibope showed the pair were tied with 40 percent each.

Brazil’s election is one of the most turbulent seen since the country’s return to democracy three decades ago, coming after over four years of unprecedented graft investigations revealed stunning levels of political corruption. That has fanned voter disdain toward the political class, adding to the frustrations of an economy that continues to sputter.

Bolsonaro, 63, has campaigned as the man who will sweep away political corruption and stop the return of the PT, which many blame for Brazil’s recent recession, its worst in decades.

Haddad, 55, a former Sao Paulo mayor, has presented himself as a moderate and is hoping to draw the votes of supporters of Lula, who is still Brazil’s most popular politician despite being in jail for corruption and barred from running for office.

Bolsonaro has been hospitalized since he survived a Sept. 6 assassination attempt, when an assailant stabbed him during a street campaign rally. Bolsonaro has said he will not return to campaigning before the first-round vote.

The poll showed Bolsonaro had the highest rejection rate, at 46 percent, which could work against him in a runoff. Haddad had a 30 percent rejection rate, indicating his support had room to grow.

Center-left candidate Ciro Gomes was flat at 11 percent in the Ibope poll, and the favorite of investors, Geraldo Alckmin, was at 8 percent. Environmentalist Marina Silva has 5 percent.

The poll, which interviewed 2,506 people on Saturday and Sunday, had a margin of error of two percentage points.