Zimbabwe's former president Robert Mugabe, who was ousted in November, has said he would not vote for his successor Emmerson Mnangagwa in the presidential election.
"For the first time ever we have now a long list of aspirants to power," Mr Mugabe said.
"I cannot vote for those who tormented me... I will make my choice among the other 22 (candidates) but it is a long list," he added at a press conference in Harare.
"I can't vote for ZANU-PF... what is left? I think it is just Chamisa".
Mr Mnangagwa and his rival Nelson Chamisa held final election rallies yesterday and both vowed to rebuild an economy shattered by Mr Mugabe's long rule.
Tomorrow's vote is the first since Mr Mugabe was forced to step down in November after a de facto coup and, as such, is a major national test.
Mr Mnangagwa is favourite although the latest opinion poll said the race was too close to call.
The run-up to the presidential and parliamentary election has been peaceful compared to previous polls but there are reports of intimidation and coercion in rural constituencies, and state media is biased towards the ruling ZANU-PF party.
A run-off will be held in September if neither candidate wins outright.
Little separates the two men's policies but Mr Mnangagwa is 75 and represents the war generation that has ruled since independence in 1980, while Mr Chamisa, a 40-year-old lawyer, embodies the hopes of many young people.
The election could confirm the country's rehabilitation after years as a pariah under Mr Mugabe and help unlock foreign investment, especially if western observers, monitoring for the first time since 2002, declare it fair.
Mr Mnangagwa held senior positions in Mr Mugabe's governments as head of internal security and vice president but since coming to power has cast himself as a reformer with his Zimbabwe is "open for business" mantra.
Mr Mnangagwa has outspent Mr Chamisa on the campaign trail, buying all-terrain double cab vehicles for more than 300 ZANU-PF parliamentary candidates.
He has occupied most billboards in major towns and dominated the airwaves with adverts.