From noon on Sunday, mediator President Thabo Mbeki struggled to strike the accord that would start a transitional era marking the end of Mugabe’s blood-soaked 28 years in power. By midnight, there was still no deal in sight.
The six negotiators from both factions of the Movement for Democratic Change and Zanu-PF, in talks under South African mediation for the last two weeks, remained outside the closed doors of the 17th floor of a 5-star hotel where Mugabe and Tsvangirai struggled to find common ground.
Tsvangirai, who beat Mugabe in the March 29 elections, but pulled out of the second round because Zanu-PF militia murdered so many of his officials and supporters before polling day, argued that both he and his party had won majority support in the elections.
By late on Sunday night, the relaxed atmosphere at the hotel, where a rich Harare family had gathered for a sumptuous wedding feast, began to chill as even the state press began to realise the easy deal they had predicted was slipping away.
There was an assumption by several of them that the "deal", as the state-controlled Sunday Mail called the negotiations, was hours away and would be in place before Monday – one of the most important days of Mugabe’s calendar, the annual Hero’s Day commemoration at the national shrine in honour of those who fought and died to end white rule.
The hotel, surrounded by members of Mugabe’s Presidential Guard, was also swarming with intelligence operatives and cabinet ministers.
Many of them face the end of their political careers, even if Mugabe retains significant executive power as an agreement on a new transitional cabinet has agreed, with almost equal members from each party in a transitional authority.
Some of the hardliners fanatically loyal to Mugabe are as unacceptable to many younger members of Zanu-PF as they are to the MDC.
It was expected, if an agreement was reached, that Mugabe and Tsvangirai would have equal numbers of cabinet ministers and one or two for the smaller MDC faction led by Arthur Mutambara.
The length of the transitional period was not considered vital, according to political sources, as an agreement had been reached by all parties that a new constitution would be hammered out within a specified time frame, and then presented to the people – leading to fresh elections.
If no deal is reached, then Mugabe faces an economy that is unravelling daily and no foreign currency to import food.
"I cannot even begin to wonder what is happening in Harare at the negotiations, as here we are fighting over food," said an MDC MP from southern Zimbabwe on Sunday.
"Here there is no maize, and peasants from my area who tried to buy some from the state have been cheated out of what they paid for by Zanu-PF people and the police. The maize they paid for was taken by police and the district administrator.
"We know children were beginning to starve last week. I am trying to manage the situation from Bulawayo, as I cannot go to my constituency as police are always arresting me there."
Mugabe banned humanitarian agencies from fieldwork on June 4, which means about 1,5-million people in need of emergency feeding programmes now are going hungry.
In Chitungwisa, a dormitory town on the southern tip of Harare, people say they have not even been able to find the staple food, maize meal, on the black market for the past four days.
"Honestly, we really have nothing to eat but vegetables now," said a clerk at a city centre drycleaning outlet.
Zimbabwe’s most prominent civil rights activist, Lovemore Madhuku, warned on Sunday: "Morgan knows that if he sells out, there will be a tragedy and he will have betrayed the people and the struggle of the last eight years."