Vucic won about 55 percent of Sunday's vote, far above the 50-percent threshold required to win in the first round.
Vucic won about 55 percent of Sunday's vote, far above the 50-percent threshold required to win in the first round, the results based on more than 90 percent of polling stations released by the state electoral commission showed.
Two obstacles for EU membership talks, started in 2014, seem to have been removed.
Vucic's predecessor Tomislav Nikolic, a pro-Russian member of his Serbian Progressive Party (SNS), is likely to retire from political life.
And ultranationalist Vojislav Seselj, who was burning European flags to show his opposition to Serbia's EU bid, won less than five percent of the vote.
But Vucic, a 47-year-old hardline nationalist turned a pro-European, still has to overcome the reluctance of a large part of his electorate, who cleave to historic ties with Moscow and are not passionate about joining the EU.
Vucic, prime minister since 2014, has time as the next parliamentary election is only due in 2020.
"Vucic was a candidate taking into account EU membership talks which require notably changes to the constitution and maybe new prerogatives for the president," said political analyst Jadranka Jelincic.
"We will see a sort of 'presidentialisation' in Serbia," independent analyst Boban Stojanovic told AFP.
"I expect Vucic will have the final say in all decisions."
Serbia's next government will be led by a prime minister who would be a person of trust who would not overshadow Vucic.
It would also have to follow the political "direction" that Vucic says voters chose in electing him.
"The vast majority of Serbia's citizens are for the continuation of reform, for Serbia to keep to its European path and maintain the links that we have with Russia and China," a thrilled Vucic said late Sunday.
"Vucic also expects to be the president who will lead Serbia into the European Union, which is a plausible hypothesis around 2022" when his mandate will expire, Loic Tregoures, a Balkans specialist, said in an analysis published by The Conversation website.
Both Russian President Vladimir Putin and EU Enlargement Commissioner Johannes Hahn congratulated Vucic on Monday.
Putin said Vucic's victory "testifies to the wide support for your efforts aimed at resolving current economic and social problems ... and pursuing a constructive, balanced foreign policy," a Kremlin statement said.
"Looking forward to working with new president as partners and friends on EU accession," Hahn said in a tweet.
Vucic "has been presenting himself as a pro-European ever since he took power, and gave significant signs of his involvement, such as the 2013 Belgrade-Pristina agreement" on normalisation of ties with Kosovo, Tregoures said.
Unlike most EU members, Serbia refuses to recognise the independence of Kosovo, its former province populated mostly by ethnic Albanians, declared in 2008.
Normalisation of ties between Belgrade and Pristina is key regarding the path to EU accession.
With Belgrade currently negotiating judicial and fundamental rights with Brussels, no EU official voiced reserve over Vucic's campaign despite opposition claims he is authoritarian and controlling the media with an iron fist.
But after his win Serbia's divided opposition seemed weak.
Former ombudsman Sasa Jankovic, an independent candidate supported by the centre-left Democratic Party, placed second with just 16 percent of the vote, garnering support from the urban middle class and liberals opposed to Vucic, in large part by criticising the authorities and insisting on their accountability.