NEW: Datpolha reckons Brazil's President Lula has beaten Flavio Bolsonaro to win an unprecedented fourth term, coming back from behind in the first round.
With 75.87% of the vote counted, Lula leads 51.11% to 48.89%, and Detapolha says Bolsonaro can no longer close the gap.
Lula, who turns 81 on Tuesday, will be the oldest president in the country's history.