The long-awaited election results had just come in and the leader of Zimbabwe's opposition Movement for Democratic Change was facing the media to announce the way ahead. He looked exhausted. Journalists were packed into a cramped and sweaty room in the party's Harvest House headquarters in central Harare. It had been a bruising campaign.

The smell of unwashed bodies hung in the air. As soon as Morgan Tsvangirai, the man who would be the next leader of Zimbabwe, finished, he was assailed by questions from a jaundiced press corps. Based on his uncertain performance, most observers concluded his and the MDC's political future did not look good.

If Mr Tsvangirai was haunted by memories of the 2005 election campaign - when he was outfoxed for the third time by President Robert Mugabe - he did not show it on Tuesday night as he all but claimed victory in last weekend's dramatic elections. He wore a crisp dark suit. Giant MDC banners lent the occasion a modern feel. In a reflection of the money that is pouring in from donors keen to see the back of Mr Mugabe, the MDC had rented a banqueting suite in the old colonial Meikles Hotel. If his remarks had rather too many clichés to be exactly Obama-esque, they were confident, sweeping and had a presidential feel. "Our country is at the crossroads of a defining moment as we sculpt a new destiny. For years we have stood together in queues . . . and today we face a new challenge of governance . . . and of rehabilitating our beloved country."

He is not there yet. On Friday Mr Mugabe's Zanu-PF party announced he would contest a run-off in the hope of preventing that "agent of colonial white interests", as state media describe Mr Tsvangirai, from taking power. But after the tumultuous events of the past week, "President Tsvangirai", as his supporters call him, is closer to holding that title legitimately than he has ever been.

It has been an arduous journey for the son of a bricklayer, with minimal formal education, to reach the brink of ousting the father of modern Zimbabwe. Few outside the committed circles of Zanu-PF - and there are fewer of these by the day - dispute he has earned his chance. Yet while he is clearly courageous - and refreshingly unassuming when compared with the haughty Mr Mugabe - his varied reputation as MDC leader suggests he still has something to prove.

A western diplomat who has followed his career closely compares him with Lech Walesa, the legendary Polish trade union leader turned president. They share not just a doughty record in defying an authoritarian regime but also an empathy with the working class, a true unionist's skill at mobilising people, and even the same thickset build.

Mr Tsvangirai was born in 1952 in one of the more arid and impoverished areas of rural Zimbabwe. He left school aged 16 with few qualifications to work at a nickel mine. The state media love to highlight that he did not join one of the liberation movements against white-run Rhodesia, but as the eldest of nine children, he says it was incumbent on him to help feed his family. After a decade at the mine and being promoted to the post of foreman, he worked in a textile factory before starting to rise up the union movement. It was in this capacity, that - until the MDC's defeat of Zanu-PF in last weekend's parliamentary elections - he achieved arguably his greatest successes.

As head of the Zimbabwe Congress of Trade Unions he led a series of strikes which in the late 1990s forced Mr Mugabe to negotiate with him face to face, and agree to a string of concessions. Since moving into national politics in 1999 with the formation of the MDC, he has had a far more difficult time as he shifted from leading a close-knit force of like-minded workers to steering a national coalition of people from very different social and political backgrounds, united only by the goal of ousting Mr Mugabe.

His political skills are indisputable. He has that invaluable asset of appearing comfortable in his own skin. His banter electrified crowds at rallies in the heartland of his fellow Shonas (Zimbabwe's majority tribe). "Some of you who are dark," he told crowd after crowd, "it's not because you are dark but because you have no money for soap." In a country where inflation is up to 400,000 per cent and few can afford a bus fare let alone soap, the line went down a storm.

But his leadership record has a more controversial side. His critics accuse him of changing his mind, depending on the opinion of the last person he has spoken to, and of having an autocratic streak. Due to these tensions many of the more intellectual figures in the party's leadership seceded and formed a rival MDC wing in October 2006.

They suggest he is uncomfortable in the presence of people better educated than him, that he has ridden roughshod over the party's constitution, and that he failed to discipline party activists guilty of violence against fellow MDC members. Another charge is that he has on occasion shown a marked lack of judgement.

Mr Tsvangirai rolled his eyes wearily when asked by the Financial Times about the charge of intolerance and said his critics were confusing autocracy with strong leadership. His friends say he is often underestimated. "It's where a lot of intellectuals have fallen flat on their backs," says Theresa Makone, a member of his inner circle and a close friend of his wife Susan, with whom he has had five children. "He thinks leadership is not about the number of degrees you have."

Another old friend, who would not be identified, highlights the pressure he has faced just to keep the movement going. Several hundred of the MDC's supporters have been killed by state-sponsored gangs and the security forces in the past eight years, including Mr Tsvangirai's election agent and driver who were doused in petrol and burned to death in their car. He himself has been arrested several times. He was brutally beaten by the police last March when he led a demonstration through central Harare.

The MDC's victory testifies to Mr Tsvangirai's perseverance - a strength he will need to draw upon once again in the coming weeks as he goes head to head with Mr Mugabe.

If he succeeds in ousting Mr Mugabe he faces a new challenge. The recent history of southern Africa is littered with cases of "new broom" politicians ousting independence leaders and then proving disappointments, notably in neighbouring Zambia and Malawi. He would have to prove his critics wrong and buck that trend.