With nearly all ballots counted from an election that saw a 77 percent turnout, Yushchenko had just over 52 percent of the votes and Yanukovych 44.2 percent.
Speaking at Kiev's Independence Square, where mammoth crowds gathered for weeks to protest fraud in last month's election, a jubilant Yushchenko told supporters: ''Thousands of people that were and are at the square were not only waiting for this victory but they were creating it."
Yanukovych refused to concede defeat, telling reporters he would go to the Supreme Court to challenge the results once the election commission released its final tally.
Later, however, he said he had lost respect for the court because of its ruling that annulled the results of the earlier election, which Yushchenko's camp, international observers, and even members of the Central Electoral Commission assailed as fraudulent.
The court's ruling ''breached the constitution and the law," Yanukovych said. ''Today, I can't have faith in such a chamber."
An international delegation of observers said that with Sunday's revote, Ukraine had made good progress toward meeting international standards for elections.
''It is our judgment that the people of this great country have made a great step forward to free and fair elections by electing their future president," said Bruce George, head of the delegation from the Organization for Security and Cooperation in Europe, the Parliamentary Assembly of the Council of Europe, and other election watchdogs.
Thousands of people celebrated in Independence Square last night, but their numbers were far smaller than the hundreds of thousands who jammed the plaza at the height of the protests last month. ''Today is a golden day," said Mykola Rak, a 62-year-old sporting an armband of orange, Yushchenko's campaign color.
