Lula and Bolsonaro statistically tied in potential Brazil runoff, polls suggest

SAO PAULO, Sept 21 (Reuters) - Brazilian President Luiz Inacio Lula da Silva and Senator Flavio Bolsonaro remain statistically tied in simulated runoffs ahead of next month's election, two polls showed on Monday.

Bolsonaro leads Lula by one percentage point in a Quaest poll, while Lula is ahead by one point in a separate BTG Pactual/Nexus poll. They remain statistically tied since the advantages are within the margin of error.

Bolsonaro, son of the former President Jair Bolsonaro, would receive 42% of voter support in a potential runoff, against 41% for Lula, a Quaest poll showed late afternoon.

The previous Quaest poll , released on September 14, showed Bolsonaro at 42% and Lula at 40%.

If no candidate wins more than 50% of valid votes in the October 4 first round, the two frontrunners advance to a runoff on October 25.

In a first-round scenario, Quaest had Lula leading with 37% of the votes, followed by Bolsonaro (33%), Cury (6%) and Caiado (4%).

Last week, the poll showed Lula at 36% and Bolsonaro at 31% in the first round.

Quaest surveyed 2,004 people from September 17 to 20; the margin of error is 2 percentage points.

Lula would receive 46% of voter support, compared with 45% for Bolsonaro in a potential runoff, a BTG Pactual/Nexus poll showed earlier in the day.

In a first-round scenario, Lula would lead with 40% of the votes, followed by Bolsonaro (37%), Augusto Cury (6%) and Ronaldo Caiado (5%).

Nexus surveyed 2,006 people from September 18 to 20. The poll also has a margin of error of 2 percentage points.

(Reporting by Rodrigo Viga Gaier in Rio de Janeiro, Michael Susin in Barcelona and Gabriel Araujo and Andre Romani in Sao Paulo; Editing by Isabel Teles)