Among Brazilians, even the poor slum dwellers, beating inflation is the number one priority, ahead of social welfare, schools and even jobs. Since Mr Cardoso stepped down as finance minister in the summer to run for president, the economic plan he masterminded has brought inflation down from nearly 50 per cent a month in June to 2 per cent a month in September - the lowest in eight years.
From being 20 percentage points behind his main opponent, the left-wing former mechanical fitter from the factory floor, Luis Inacio 'Lula' da Silva, Mr Cardoso, 63, a former sociologist, was 23 points ahead at the weekend. But about 15 per cent of voters remain undecided, so it is still possible Mr da Silva could, as he claims, force a run-off in November.
It is not just a stable currency, the real, that has transformed Mr Cardoso's fortunes. Mr da Silva, 48, leader of the Socialist Workers' Party (PT), who was tipped as favourite only three months ago, did himself no favours when he denounced Mr Cardoso's economic plan as an electoral manoeuvre and, worse, offered no anti-inflation plan of his own.
Mr da Silva had been touted - even among the middle classes - as a possible saviour, following the sleaze that engulfed the political establishment under the rule of the right-wing, whizz-kid president, Fernando Collor de Mello, impeached for corruption in 1992. The right wing, demoralised and divided, calculated that none of its candidates had the charisma or moral authority to match Mr da Silva, a plain-speaking, astute union leader, on whom no hint of corruption could be pinned.
So they closed ranks - some would say, hid - behind Mr Cardoso, from the small reformist PSDB party, a man with good democratic credentials who had written the internationally renowned study Dependence and Development in Latin America while in exile in Chile during Brazil's military dictatorship in the late 1960s. Mr da Silva started to lose his lustre as Mr Cardoso's personal integrity and political moderation became evident. Working-class Brazilians, traditionally reluctant to elect one of their own to rule over them, were attracted. Mr da Silva was fatally slow to react.
Should Mr Cardoso win, his critics say, he will be trapped by his conservative allies, especially the far-right Liberal Front (PFL), the party of Mr Cardoso's running mate, Marco Maciel. The PFL's power base is in the impoverished regions of the north-east, where big landowners and powerful local bosses rule as they have done for more than a century. Mr Cardoso's reform plans, particularly his tentative gestures towards land reform will, many fear, be stifled.
The Da Silva camp is expected to increase its showing in Congress: the PT is predicted to return five senators - it has one at present - and its group of MPs, currently 35, could rise to 80. Mr Cardoso's PSDB may do the same, and other left-centre victories could, estimates say, bring the number of left-wing MPs up to 300, a parliamentary majority.
Theoretically, Mr Cardoso could then break free and champion the left. But in Brazil the presidency is far more powerful than the legislature. And in any case, the last time a Brazilian president took such a course, confronting the landowners on the issue of agrarian reform in 1964, a military coup followed. Rule by the generals lasted more than 20 years.
Millions of Brazilians will be untouched by all of this. Of Brazil's 150 million people, the government reckons 64.5 million are 'in poverty', meaning that they earn less than the minimum wage of 70 reals ( pounds 51) a month. Of them 32 million 'go hungry'. Voluntary agencies working with the poor say that these millions have no effective share in the structures of civil society and are powerless to extract favours from whichever candidate may be elected today.