Formel Rebel Gustavo Petro narrowly won a runoff election over a political outsider millionaire Sunday

ushering in a new era of politics for Colombia by becoming the country's first leftist president.

Petro, a senator in his third attempt to win the presidency

got 50.48% of the votes

while real estate magnate Rodolfo Hernández had 47.26%

with almost all ballots counted, according to results released by election authorities.

Petro's victory underlined a drastic change in presidential politics for a country

that has long marginalized the left for its perceived association with the armed conflict.