The move ended a weekslong standoff with international donors. U.S. Secretary of State Hillary Rodham Clinton had made a last-minute visit in the midst of the Egypt crisis to reiterate personally to Preval that Washington supported the Organization of American States recommendation that ruling-party candidate Jude Celestin be dropped from the ballot.
The early morning announcement that first-place candidate Mirlande Manigat will face popular singer Michel "Sweet Micky" Martelly prompted cheers of relief in the surrounding suburbs of the capital, where residents had feared a repeat of pro-Martelly riots in December after preliminary results showed Celestin as the No. 2 vote-getter.
That joy was surpassed by the reaction abroad.
"It's a great day in Haiti today again. We had some positive results from the (electoral council) earlier this morning," U.S. Ambassador to Haiti Kenneth Merten told reporters in Washington. "We are pleased to note that they seemed to have been very diligent in following the OAS verification mission's report's recommendations."
Governments that have collectively spent billions on Haiti's stalled recovery from last year's earthquake - and pledged billions more for reconstruction - wanted to see an acceptably elected government in place to continue with their investment, aid and reconstruction plans.
International frustration with Preval was high. The U.S. suspended visas to a number of officials in the lead-up to the final results as rumors swirled that Celestin would be given a spot in the runoff. U.S. Ambassador to the U.N. Susan Rice said support depended in part on following the OAS recommendations.
On Thursday, U.N. deputy spokesman Farhan Haq said that Secretary-General Ban Ki-moon welcomed the final results and "encouraged all actors to take advantage of this opportunity to move forward with the electoral process."
An OAS expert team was brought in to sort through a messy first round election on Nov. 28 that was nearly derailed by fraud, disorganization, voter intimidation and calls by candidates - including Martelly and Manigat - to throw out the vote while polls were open.
Though international observers initially said problems had not invalidated the election, the Dec. 7 announcement that Celestin could advance and subsequent rioting prompted immediate statements by the U.S. Embassy and others questioning the results.
Some, including members of the U.S. Congress, called the OAS report a whitewash and foreign meddling in Haitian affairs.
On Thursday, U.S. Rep. Maxine Waters said the United States, Canada and France "used (their) tremendous power and influence to determine the outcome of the first round" and denied Haitians "the opportunity to express their will." The left-leaning Center for Economic and Policy Research called it "a big setback."
Both said the race was fundamentally flawed because it excluded the party of exiled former President Jean-Bertrand Aristide, who remains popular among many Haitians and has a dedicated following overseas.
But many Haitians, especially in the capital, said they were happy with the result.
"If people didn't vote for the candidates we wouldn't have had these problems" in the streets, said Adlair Saintil, a 28-year-old bread vendor.
He supports Martelly because of promises to move government services and jobs to areas outside Port-au-Prince. "A lot of people died because they had to leave their hometowns," Saintil said.
The second round, originally slated for January, is now expected March 20 with campaigning set to begin Feb. 17. Final results - the naming of Haiti's next president - is not foreseen until April 16.
Preval's five-year term is supposed to end Monday. He extended his term for up to three months through a law passed by members of his party in an expiring Senate. Haitians fed up with his government protested and he pledged to step down on time, but more recently reversed course and said he wants to remain until a successor is elected.
"If him continuing in his position until a new president is elected supports stability and peace in the country then I think it's a good thing," OAS Assistant Secretary-General Albert Ramdin told The Associated Press by phone. "But this is a decision to be made by the Haitian authorities," he added.
Merten, the U.S. ambassador to Haiti, agreed. "Our goal is again to support what the Haitian people want and for there to be a peaceful turnover of power from one legitimately elected president to another," he said.
Asked about Preval's plans, his chief of staff, Fritz Longchamp, told the AP: "We have to wait until he makes a public statement."
Despite a crowded and fractured field, candidates of Preval's Inite, or Unity, party advanced to runoffs or won outright 68 of 99 races for the lower house of parliament and all but one of the 11 open Senate races.
Opponents allege Inite used fraud in those races as well. But Ramdin said that was an internal matter and that the OAS expert team focused solely on the presidential race.
Parliament ratifies - and can remove - the presidentially nominated prime minister, who serves as head of government under the president, who is head of state.
A beaming Martelly said after the runoff announcement that justice had been done.
"I don't think (foreign governments) have decided the political future of Haiti. I think that the support that they have brought to Haiti matches the people's will toward change," he said at a news conference.
Most people were just glad to have not added another problem to their often insurmountable daily struggles - poverty, the lack of rebuilding, a cholera epidemic and the lack of basic institutions.
"Everyone is very happy that the country woke up calm," said Ronald Joseph, a 37-year-old mechanic. "Hopefully we can have a second round and things will move ahead."
Associated Press writers Evens Sanon in Port-au-Prince, Bradley Klapper in Washington and Anita Snow at the United Nations contributed to this report