BRASILIA (Reuters) - Brazil’s far-right presidential candidate Jair Bolsonaro, who was stabbed in the stomach during a campaign rally last week, maintained his lead but saw no big boost in a Datafolha poll published Monday.

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The first survey conducted since the near-fatal stabbing of Bolsonaro showed he won 24 percent of potential votes among those polled, up from 22 percent in a Datafolha survey released last month. Leftist Ciro Gomes rose to second place, taking 13 percent, up from 10 percent.

The knife attack against Bolsonaro further complicated Brazil’s most unpredictable election in three decades, with its most popular politician, jailed former President Luiz Inacio Lula da Silva, banned from running in the Oct. 7 vote due to a corruption conviction.

In the likely case of a runoff ballot, the survey found that Bolsonaro would tie with Fernando Haddad, who is almost certain to be named as the Workers Party candidate this week, but would lose badly to all other top rivals.

Bolsonaro, a former army captain who favors easing gun control laws to fight crime, has stirred controversy with comments denigrating women, gays, blacks and indigenous people. He has led the field from the outset in polls that excluded Lula, by tapping into voter anger over political corruption.

Gomes, a former governor of Ceará state in Brazil’s poor northeast, showed in a Sunday night presidential debate that his attacks on Bolsonaro would not be slowed by the latter’s stabbing, when he said that the right-wing congressmen “had suffered a wound to his stomach, but it changed nothing in his head.”

Environmentalist Marina Silva fell from second to third place in the Datafolha survey, taking 11 percent, dropping 5 percentage points.

The poll by Globo TV and the Folha de S.Paulo newspaper was released as Lula spent the day in jailhouse meetings with former Sao Paulo Mayor Fernando Haddad, who remains as the vice presidential candidate on the PT ticket.

The PT’s strategy has been to keep Lula’s candidacy alive for as long as possible, then work to transfer his support to Haddad, who polled 9 percent, compared with 4 percent in the same poll a few weeks ago.

Haddad’s chances of making the second-round runoff between the two candidates who get the most votes will hinge on his ability to tap into the massive support enjoyed by Lula.

In Monday’s poll, business-friendly center-right candidate Geraldo Alckmin registered 10 percent, ticking up from the 9 percent he won last month.

Datafolha surveyed 2,804 voters across Brazil on Monday. The poll has a margin of error of two percentage points.