Bachelet and her closest rival on Sunday, Evelyn Matthei, were childhood friends and daughters of generals who found themselves on opposite sides after Chile's 1973 coup, when Matthei's father ran the military school where Gen.
Alberto Bachelet was tortured to death for remaining loyal to ousted President Salvador Allende.
The last survey by Chile's top pollster CEP found 47 percent of declared voters going for Bachelet, suggesting she has a good chance at an outright majority when voters who didn't reveal their preferences to pollsters cast ballots.
Matthei got 14 percent in the poll, which had a 3 percentage point error margin.
