There is growing pressure on Yulia Tymoshenko to concede defeat.
Supporters of pro-Russian Viktor Yanukovich are celebrating his victory as Ukraine’s new president.
This even though the final results have not yet been announced after Sunday’s run-off ballot.
But election commission officials say there is no chance of changing the score: Yanukovich will stay ahead by at least two percentage points.
This is a spectacular comeback for the man who was swept aside by the country’s Orange Revolution in 2004.
Yanukovich’s win is seen as the closing chapter for the Orange Revolutionaries, who were led by Tymoshenko and outgoing president Viktor Yushenko. He scored just five percent of the vote and came fifth in the first round of the elections.
Tymoshenko threatened to organise another revolution if she suspected fraud, but international observers have hailed the vote.
Joao Soares from the OSCE said: “The second round confirmed the assessment of the first round that most OSCE commitments were met.”
The international monitors also used the words professional, transparent and honest in their assessment.
The big question now is whether the former Soviet nation will tilt back towards Moscow after five years of pro-Western policies.