HARARE (Reuters) - Zimbabwe’s President Emmerson Mnangagwa and his rival Nelson Chamisa held final election rallies on Saturday and both vowed to rebuild an economy shattered by Robert Mugabe’s long rule.

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Monday’s vote is the first since Mugabe was forced to step down in November after a de facto coup and, as such, is a major national test. Mnangagwa is favorite 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.

Tens of thousands of MDC supporters in the party’s red colors converged in downtown Harare in a carnival atmosphere, dancing to music denouncing ZANU-PF.

“Today we are celebrating. Change is inevitable, victory is certain. If we miss our chance on Monday we are doomed for life,” Chamisa told supporters and urged them to stay at polling stations to prevent vote fraud.

A few miles away, ZANU-PF supporters met at the national stadium in green, yellow and red party regalia as the party tries to win in the capital for the first time since 2000.

Little separates the two men’s policies but Mnangagwa is 75 and represents the war generation that has ruled since independence in 1980, while 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 Mugabe and help unlock foreign investment, especially if Western observers, monitoring for the first time since 2002, declare it fair.

Mnangagwa held senior positions in 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.

“This coming Monday we will win the election. We are voting for the future. We are voting for generations to come. Together we will unlock the potential for our beloved homeland,” Mnangagwa told his party supporters.

Mnangagwa has outspent 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.