By Lisandra Paraguassu and Peter Frontini

SAO PAULO (Reuters) -Brazil’s leftist presidential candidate Luiz Inacio Lula da Silva maintains a clear lead over right-wing President Jair Bolsonaro, a poll showed on Wednesday, as the candidates scrambled to win over voters ahead of an Oct. 30 runoff.

The survey by IPEC taken over the three days since the first-round vote found Lula with 51% voter support against Bolsonaro’s 43%, with a margin of error of two percentage points.

IPEC was one of several polling firms criticized for underestimating Bolsonaro’s support in the first-round vote, which Lula won by a slimmer-than-expected 5 percentage points.

Although Lula’s lead of 8 percentage points in the IPEC poll is better than his advantage in the first-round vote, when there were 11 candidates, it is much narrower than the 14-point lead that the same pollster reported on Saturday – underscoring that it is an increasingly competitive race.

Lula and Bolsonaro are both hunting endorsements as they retool their campaigns to secure a victory in the most polarized election since Brazil’s return to democracy in the 1980s.

Centrist Brazilian Senator Simone Tebet, who finished third in Sunday’s first round and was therefore eliminated from the race, on Wednesday said she was throwing her support behind Lula.

The support of Tebet, who received nearly 5 million votes, gives the former president a boost as he pitches his campaign as a broad center-left coalition to unseat Bolsonaro.

Tebet said she would support Lula because, in contrast to Bolsonaro, he had shown commitment to Brazil’s democracy and constitution. It remains to be seen how many of her voters will follow her lead in backing the former president.

On Tuesday, Lula also secured the support of the fourth-placed candidate, leftist Ciro Gomes, who went along with the decision of his Democratic Labor Party to back Lula but who did not provide the same ringing public endorsement.

Between them, Tebet and Gomes received 7% of votes on Sunday. Lula garnered 48.4% in the first round – just shy of the majority needed for an outright victory. Bolsonaro got 43.2% of votes, beating opinion polls and fanning hope among his supporters.

Bolsonaro has secured the support of the governors in Brazil’s three most populous states – battlegrounds in the southeast where he and Lula are focusing their campaigning.

Romeu Zema, the re-elected governor of Minas Gerais, endorsed Bolsonaro, as did Sao Paulo’s outgoing governor, Rodrigo Garcia, and Rio de Janeiro’s Claudio Castro, who won his re-election bid.

The president enters the second round with wind in his sails after his success in rallying conservative sentiment, which turned his Liberal Party into the largest in both chambers of Congress in Sunday’s general election.