With 79 percent of returns in, congressman Jair Bolsonaro is leading polls with 48 percent of the votes. If he manages more than 50 percent, he will win the presidency outright. If he doesn't, he heads to a runoff with the second-place candidate.

He is trailed by Fernando Haddad, the leftist stand-in for jailed ex-President Luiz Inacio da Silva, who was barred from running. Haddad has 26 percent of the vote.

Many analysts thought that Bolsonaro would win the first round of voting but face a runoff between the two top vote-getters which he would he lose. A first round win was considered a long shot at best in a country where big parties and the public campaign financing and free ad time they command hold sway.

But little in this election has gone to plan, and Bolsonaro's strong showing reflects a yearning for the past as much as a sign of the future. The candidate from the tiny Social and Liberal Party made savvy use of Twitter and Facebook to spread his message that only he could end the corruption, crime and economic malaise that has seized Brazil in recent years — and bring back the good ol' days and traditional values.