"The returns show that we are winning convincingly, that we have won in all the 26 constituencies in Harare, an MDC stronghold where we won in only one constituency in March. That is the trend," Mugabe said in footage from a relative's funeral held late on Saturday.
"Today [Saturday] I was looking at the ballots ... everywhere in Harare, not even one went to the MDC," he told a cheering crowd.
"I don't know if they have finished [tallying], but that is what it was, not even one [went to the opposition]."
In the first round of voting, the opposition took 25 out of the 26 constituencies that make up the capital.
Mugabe stood unopposed in the second round run-off on Friday after Morgan Tsvangirai, the opposition Movement for Democratic Change candidate, boycotted the poll complaining of violence and intimidation.
On Sunday, Human Rights Watch said it had documented numerous incidents of voters being coerced into taking part in the run-off, and other being attacked after polling was completed.
The US-based group said in a statement that people who did not have the inked finger which showed they had voted were taken away and beaten with batons and thick sticks.
It also called on African leaders to impose sanctions against Zimbabwe's government and refuse to recognise the legitimacy of Mugabe's expected victory.
"African states should impose sanctions against Robert Mugabe and his illegitimate government in Zimbabwe after the sham presidential run-off," the statement said.
A group of African politicians who observed the election have called for a new round of polling, dismissing Friday's vote as neither free of fair.
"The political environment throughout the country was tense, hostile and volatile ... characterised by an electoral campaign marred by high levels of intimidation, violence, displacement of people, abductions, and loss of life," Marwick Khumalo, head of the Pan African Parliament mission, said.
"Conditions should be put in place for the holding of free, fair and credible elections as soon as possible."
The MDC, suffered a major blow overnight when South Africa blocked a move at the UN to declare the election illegitimate.
The United States and its European allies had pushed for a resolution that would have stated the results "could have no credibility or legitimacy" but South Africa argued the Security Council was not in the business of certifying elections.
The council instead merely issued an oral statement expressing "deep regret" that the election went ahead after widespread calls for it to be shelved.
Afterwards Tsvangirai accused of Thabo Mbeki, the South African president and Zimbabwe mediator, of lobbying for Mugabe to be recognised as a legitimate head of state.
"I have received information that President Mbeki is lobbying at the African Union to have that position [that Mugabe is president] taken," he told the Johannesburg-based Sunday Times.
|Tsvangirai, who won the first election in March, boycotted the poll [AFP]
"For President Mbeki to promote Mugabe in these circumstances flies against the grain of international opinion, disregards the feelings of Zimbabweans and undermines again his credibility in the mediation effort."
Mbeki has so far made no comment since the ballot and on Saturday flew to Egypt for of an African Union summit which Mugabe is also expected to attend.
African foreign ministers meeting in the resort of Sharm el-Sheikh ahead of the summit said that getting Mugabe and Zimbabwe's opposition to talk would have better results than punitive measures.
Moses Watangula, the Kenyan foreign minister, said the route of sanctions may not be helpful for the southern African country.
Ralph Black, the MDC's representative in the United States, told Al Jazeera that a government of national unity may diffuse the current crisis.
"They must agree to form a government of national unity," he said.
"The two parties must come together to select and share power, but we believe Mugabe must not be part of a unity government - this is because the destruction of Zimbabwe's democratic institutions lies squarely at his feet."
Briggs Bomba, a Zimbabwe activist for Africa Action, a non-profit organisation, also told Al Jazeera the strategy the MDC is using has not been effective.
"What the MDC could have done was to mobilise mass popular support inside the country," he said.
"If Zanu-PF supporters, government officials, and the police, saw massive support for the MDC, and saw the people rally in large numbers in support for a change of political direction in the country, they themselves will be forced to re-think their roles as enforcing the policies of Robert Mugabe."
Tsvangirai won the first round of the election on March 29, falling just short of the 50 per cent threshold needed to avoid a run-off.
But he decided to pull out of the run-off last weekend after the MDC claimed nearly 90 of its supporters had been killed in attacks by pro-Mugabe thugs and some 200,000 voters disenfranchised after being driven from their homes.
Amid widespread reports that the electorate was being coerced into voting for Mugabe, Tsvangirai advised followers on Friday against futile gestures of defiance in what he derided as an "exercise in mass intimidation".
Turnout was "massive" in the election, the official newspaper The Herald reported on Saturday, but provided no figures.