South Africa's ruling ANC was to elect its leader on Tuesday with all the signs at a bitter party conference pointing to defeat for President Thabo Mbeki at the hands of his arch rival.
Jacob Zuma will cap a remarkable political comeback if he can topple the man who has led South Africa for the last eight years and who sacked him as deputy head of state in 2005 after his financial advisor was jailed for corruption.
While Mbeki has two years left as state president, his authority could be critically undermined by defeat, with some commentators predicting he could face efforts by Zuma's camp to force him out of office early.
The two men were formally nominated on Monday night after lengthy behind-the-scenes squabbles over ballot procedures held up the start of the process for over 24 hours.
In an apparent sign that Mbeki was losing the battle for control of the party governing South Africa since the end of apartheid in 1994, Zuma's choices as his chief lieutenants received an overwhelming show of hands from delegates.
A beaming Zuma watched the proceedings alongside a visibly downcast Mbeki, who has seen a number of his chief allies booed by delegates since the conference started Sunday.
Zuma, 65, is hoping a party victory would pave his way to the state presidency when
Mbeki's constitutionally limited two-term stint in office ends in 2009.
He has won the backing of five of the ANC's nine provincial branches as well as the women's and youth leagues in a round of primaries, making him the clear frontrunner.
Given the ANC's large majority in parliament, a victorious Zuma would normally be almost guaranteed the job of state president in two years' time.
But he faces being charged with corruption after losing a recent court bid to have a series of search warrants declared illegal.
Mbeki was not going down without a fight, urging delegates in his opening address to elect leaders "seized with ethical fervour".
Hundreds of Mbeki supporters staged a show of strength outside the conference hall on Monday as many more gathered for a lunchtime rally in a local sports stadium.
As tensions mounted, security guards had to separate delegates at one stage, as Mbeki supporters taunted Zuma followers with three finger signals in solidarity for their candidate's bid for a third term.
Zuma's followers responded with a two-handed rollover motion to indicate their wish for change at the top.
Zuma, whose earthy charm contrasts sharply with the aloof Mbeki, has cashed in on growing disillusionment about the government's failure to eradicate poverty.
Although Mbeki can point to an uninterrupted period of growth, unemployment is unofficially estimated to be around 40 per cent.