Mr Fernando de la Rua, president-elect for the opposition Alliance coalition, announced that he had "come to recover the dignity of the Argentinian people", as yesterday's official results confirmed his crushing victory over the Peronist candidate, Mr Eduardo Duhalde.
"We are going to put an end to all forms of corruption and impunity and guarantee respect for all Argentinians," added Mr de la Rua, who won 50 per cent of votes, underlining the key aspects of his successful campaign.
The Alliance victory celebration was tempered by disappointment at the news that Ms Graciela Fernandez Meijide, candidate for governor of Buenos Aires Province, had lost to Peronist rival Mr Carlos Ruckauf, despite exit polls suggesting the opposite.
Mr Ruckauf, a controversial figure who signed a 1975 decree legalising the extermination of dissidents, was confirmed the winner early yesterday morning, having secured 48 per cent of votes.
The victorious Alliance, composed of centre-right Radical Civic Union and centre-left Front for a Country of Solidarity (Frepaso), won 18 new parliamentary seats, making them the strongest single force in congress, falling just five seats short of an absolute majority.
The Peronist party now has 102 parliamentary seats, having lost 20 in this election. This leaves the balance of power between smaller provincial parties and the third-place presidential candidate, Mr Domingo Cavallo, whose right-wing Action for the Republic party won 12 seats.
The Peronist presidential defeat marked the worst electoral result for the party since Juan Peron first launched his movement in February 1946, with outgoing President Carlos Menem set to retake his position as party chief and launch an internal reshuffle.
Mr de la Rua called on his political rivals to "leave behind selfishness and small-mindedness", saying he would seek dialogue with the defeated Peronists to ensure peaceful cohabitation. The Peronists still hold a majority in the Senate and the support of five out of nine Supreme Court judges.
"It's time to build a strong integrated Latin America, a powerful Mercosur with a commitment to co-operation," he said, suggesting that his international priority would be the regional common market, Mercosur, which links Brazil, Argentina, Uruguay and Paraguay in a free trade zone serving 280 million people.
The Mercosur project has been slowed down by trade disputes and political unrest, as Brazil and Argentina bicker over textile and footwear tariffs, while the political asylum granted to Paraguay's Lino Oviedo, a failed coup general, damaged relations between the two countries.
"If I become president on December 10th [inauguration day]," said Mr de la Rua, "Oviedo is out of here the next day."
The new president's first trip outside Argentina will be to Brazil, where social democrat President Fernando Henrique Cardoso is a political ally.
In Uruguay, analysts predicted that the de la Rua victory would have a knock-on effect for socialist candidate Mr Tabare Vazquez, favourite to win the presidential elections next Sunday.
Mr Ricardo Lagos, Chile's Socialist Party candidate tipped to win the upcoming presidential elections, flew into Buenos Aires on election night, symbolising the political and personal connection between the two leaders.
The realignment of political forces in the region suggests that voters are weary of the prevailing free-market economic model which has left millions in poverty. The conservative daily La Nacion published a study last week showing that 1,000 Argentinians fall beneath the poverty line every day, a reminder that while Mr Menem's 10-year rule brought economic stability, it also increased social inequality.
Mr de la Rua's economic team is currently drawing up an austerity plan which would combine budget cuts with a taxation drive and fresh credits for small and medium businesses, considered the engine of any economic recovery.
The Alliance has pledged to continue its investigation into corruption, with speculation that Mr Menem may eventually be called to testify on the activities of former ministers. "There will be no witch-hunt, however," said Mr Eugenio Zaffaroni, director of the Alliance anti-corruption squad.
Meanwhile, Mr Menem opened the doors of his re-election campaign headquarters yesterday and his posters were due back from the printer, even as city garbage collectors swept away tonnes of rubbish from the campaign just ended.