He will now be sitting down with men who have arrested and beaten him and his supporters for years and have no interest at all in making a success of the new government.
Mr Mugabe, 84, who is in denial about the failings of his leadership and particularly the violence unleashed by his henchmen, will relish a more grandfatherly type of role, modelling himself on Nelson Mandela – the man he considers usurped his position as Africa’s greatest hero.
Mr Mugabe, who treats opposition figures like recalcitrant children, can be very benign on a one-to-one basis, in sharp contrast to his henchmen who control the security services and fear that the new government may try to pursue them in the courts.
These men, who have effectively run the country through the shadowy Joint Operational Command (JOC) since the disputed elections at the end of March, have said time and again that they will not serve a man such as Mr Tsvangirai, who did not fight in the guerrilla war of independence.
Whether the deal works or collapses before the ink is dry will depend largely on the details, particularly the amount of power Mr Mugabe will still retain and how he uses it.
With inflation at 11 million per cent and the food shelves bare, Mr Mugabe had no option but to agree this deal. If the economic situation improves, he and his supporters may well try to wriggle out of some of the concessions they made. It would not be the first time that Mr Tsvangirai, never the sharpest of politicians, has been duped. His opponents would be only too happy for his reputation to be damaged by poor government, and the scale of the task before him is so enormous that it is hard to see how he can possibly meet the aspirations of the long-suffering population.
Here, the much maligned President Mbeki of South Africa will be critical. Mr Mbeki has worked to achieve this accord and with his term of office ending next year he will be keen to make sure it does not unravel. His role in ensuring the adoption of a new constitution that severely reduces the power of the president will be critical.
Mr Mbeki, the official mediator of the Southern Africa regional grouping, SADC, has said that the new government and the deal that led to it will be unveiled on Monday at a ceremony attended by regional heads of state.
SADC endorsement will make it hard for Britain and the European Union not to deliver on a promised multimillion-pound rescue package, even though it will stick in the throats of many effectively to bail out Mr Mugabe while he is still in office.
Mr Mugabe’s appetite for power has waned in recent months. He may decide to step down in six months to a year, but has made it clear that he will only allow real power to be wielded by members of the ruling Zanu (PF) party.
The new government will therefore be dogged by in-fighting and power struggles. But the world will hope that the violence will no longer be on the streets.