Centrist senator Rodrigo Paz was leading Bolivia's presidential election, according to early official results, which showed the ruling Movement for Socialism on track for its worst election defeat in a generation.

With the last campaigns only one day in the rearview mirror, Bolivia’s political world has delved into preparations for an unprecedented runoff election that will reveal the extent of a centrist senator’s unexpected traction in the presidential vote.

A dark horse centrist, Sen. Rodrigo Paz, drew more votes than the right-wing front-runners, although not enough to secure an outright victory, early results showed.