Populist Peter Pellegrini has been elected president of Slovakia, succeeding the liberal Zuzana Caputova.
Mr Pellegrini, 48, defeated the pro-Western Ivan Korčok, a former diplomat, with 53% of the vote.
A former prime minister, he is an ally of Prime Minister Robert Fico, and shares the PM's dovish attitude towards Russia.
Mr Fico and his allies now control Slovakia's parliament, government, and soon the president's office.
Slovakia had been one of Ukraine's staunchest allies before Mr Fico came to power in October on a pledge to halt supplies of Slovak Army military stocks to Kyiv. With Mr Pellegrini replacing Mrs Caputova, Ukraine has now definitively lost a voice of support in an EU and Nato capital.
Mr Fico has called for an end to Western military support for Ukraine, an immediate ceasefire, and peace talks with Moscow. He said recently President Vladimir Putin had been "unfairly demonised" and argued admitting Ukraine to Nato would mark the beginning of a third world war.
Mr Pellegrini's campaign echoed some of that Moscow-friendly rhetoric, accusing Mr Korčok of being a warmonger who would send Slovak soldiers to fight in Ukraine - a constitutional power the president does not have.
On Sunday Mr Pellegrini vowed "to ensure that Slovakia remains on the side of peace and not on the side of war".
"You don't have to worry that the Presidential Palace, as it has been for the last 10 years, will become a centre of oppositional, opportunistic power that will harm the government, that will harm the state abroad and will rejoice in the failures of the Slovak government," he said.
Once Mrs Caputova steps down in June, there will no longer be any high-level official in Slovakia - a country which barely a year ago donated its entire fleet of MiG-29 aircraft to Ukraine - who unequivocally backs Kyiv's effort to defend its territory with force.
Mr Korčok expressed his anger at Mr Pellegrini's campaign tactics, saying it was fear that decided the outcome of the election, and "that fear was spread by those who are hidden in state positions".
He said of the result: "It turns out that it is possible to become President of the Slovak Republic not only by spreading hatred, whipping up passions and pushing people to the barricades, but also by painting the opposite number, that is to say, me, as a candidate of war. I will not forget this."
The liberal pro-Western opposition also accuses Mr Pellegrini - as head of the coalition Hlas party and chairman of parliament - of remaining silent as Mr Fico took a wrecking ball to Slovakia's criminal justice system, notably abolishing the Special Prosecutor's Office, which was set up 20 years ago to probe serious corruption and economic crime.
It had investigated a number of senior officials in Mr Fico's Smer party, and had been overseeing the prosecution of those believed to be responsible for the murder of investigative journalist Jan Kuciak and his fiancée Martina Kusnirova in 2018.
The killings were a seismic event in Slovak politics. The fallout ended Mr Fico's second premiership in 2018 and led to the liberal, pro-Western Zuzana Caputova being elected president on a wave of popular anger at official corruption and organised crime.
Robert Fico's government recently set its sights on Slovakia's public broadcaster, submitting plans to abolish the institution and replace it with one under virtual state control. Those plans were put on the back burner after a surprisingly poor showing from Peter Pellegrini in the first round of the presidential election two weeks ago.
The opposition fears a reinvigorated Robert Fico will resubmit them - and they say President-elect Pellegrini is unlikely to stand in his way.
