Pro-Western candidate Nicusor Dan has unexpectedly beaten hard-right populist George Simion in the Romanian election.
Mr Simion, 38, and his rival - a centrist who's mayor of Bucharest - faced off in the second round of the contest.
According to the official tally, Mr Dan was leading by nearly nine percentage points with more than 98% of the votes counted.
There aren't enough votes remaining for Mr Simion to make a comeback.
After exit polls suggested he wasn't going to win, Trump-supporting Mr Simion rejected the result and said estimates put him 400,000 votes ahead.
Speaking after voting ended, Mr Simion said his election was "clear" as he posted on Facebook: "I won!!! I am the new President of Romania and I am giving back the power to the Romanians!"
Romania's last election was annulled after its highest court ruled the leading candidate, nationalist Calin Georgescu, should be disqualified due to claims of electoral interference by Russia.
The result is surprising because in the first round, 38-year-old Mr Simion, founder of the right-wing Alliance for the Unity of Romanians (AUR), took 40.96% of the vote - almost 20 points ahead.
An opinion poll on Friday had it much closer, but still suggested the two men were virtually tied.
Mr Dan, a 55-year-old mathematician, is running as an independent and has pledged to clamp down on corruption.
He is also staunchly pro-EU and NATO, and has said Romania's support for Ukraine is vital for its own security.
When voting closed on Sunday at 9pm local time, 11.6 million people - about 64% of eligible voters - had cast ballots. About 1.64 million Romanians living abroad also took part.
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The election is being closely watched across Europe amid a rise in support for President Donald Trump.
After polls closed, Mr Dan said "elections are not about politicians" but about communities and that in the latest vote "a community of Romanians has won, a community that wants a profound change in Romania".
"When Romania goes through difficult times, let us remember the strength of this Romanian society," he said.
"There is also a community that lost today's elections. A community that is rightly outraged by the way politics has been conducted in Romania up to now."
(c) Sky News 2025: Nicusor Dan beats hard-right favourite George Simion in Romanian election
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