Zimbabwe's top court Friday dismissed an opposition bid to have presidential election results annulled over alleged rigging in favour of Robert Mugabe's successor, Emmerson Mnangagwa.

"In the final analysis, the court finds the applicant has failed to place before it clear, direct, sufficient and credible evidence" of irregularities, said Chief Justice Luke Malaba in his ruling at the Constitutional Court in Harare.

"Emmerson Dambudzo Mnangagwa is duly declared winner of presidential elections held on the 30th of July 2018."

Analysts had widely predicted the court would rule against the Movement for Democratic Change party's legal challenge.

Malaba dismissed the application with costs after strongly criticising the MDC's case.

Mnangagwa, of the ruling ZANU-PF party, won the election with 50.8 percent of the vote -- just enough to meet the 50 percent threshold needed to avoid a run-off against MDC leader Nelson Chamisa, who scored 44.3 percent.

Lawyers for the MDC had argued on Wednesday that the results should be annulled due to alleged "massive doctoring" of the vote.

Thembinkosi Magwaliba, representing Mnangagwa, had rubbished claims that the opposition had produced any evidence of fraud.

"This application was not seriously done. The applicant is clearly flippant," he said.

Mnangagwa's inauguration should now take place within 48 hours of the court's ruling, according to the constitution

A new chapter?

Nine judges, led by Chief Justice Malaba, delivered the unanimous verdict at the court in Harare, amid tight security though there were no protests ahead of the ruling.

In a first for the country, the proceedings were broadcast live on state television.

Mnangagwa, who has vowed to revive Zimbabwe's ruined economy, had hoped the elections would draw a line under Mugabe's repressive 37-year rule and open up a stream of foreign investment and aid.

Campaigning was more open than previous votes, but the election was marred by the army opening fire on protesters, killing six, allegations of vote-rigging and a crackdown on opposition activists.

The MDC has cited a catalogue of discrepancies including incorrect counting, fake "ghost" polling stations, and at some polling stations more ballots being counted than there were registered voters.

Derek Matyszak, a legal expert at the University of Zimbabwe, had predicted that the opposition faced an uphill struggle given the courts' historic tilt towards ZANU-PF, which has ruled since independence from British colonial rule in 1980.

"The outcome (was) pretty predictable," Matyszak told AFP.

The MDC's appeal, which was lodged hours before the deadline on August 10, forced Mnangagwa's inauguration -- planned for August 12 -- to be postponed.

International monitors largely praised the conduct of the election itself, although EU observers said that Mnangagwa, a former long-time Mugabe ally, benefited from an "un-level playing field".

The court could have declare a winner, call another election, or order a run-off or recount.