Ilham Aliyev has been elected to succeed his father, Heydar, as president of Azerbaijan in Wednesday's elections.
Opposition supporters clashed with police in Baku
Electoral officials said that, with most of the votes counted, Mr Aliyev, currently the prime minister, had polled 79.5% of the vote - giving him an outright win in one round.
The election was marred by violence, as riot police clashed with opposition supporters who accused the government of rigging the election.
At least two people died in the clashes.
Observers from the Organisation of Security and Co-operation in Europe (OSCE) also denounced the poll, saying that it had not met international standards.
"This election was a missed opportunity for a genuine democratic election process," said OSCE observation mission head Peter Eicher.
He cited instances of ballot-stuffing, and interference in the voting and counting processes.
President Heydar Aliyev is standing down after 30 years on and off in power.
It is the first time power has been transferred from father to son in the former Soviet Union.
The ailing president, who has spent the last three months in hospitals abroad, withdrew from the election two weeks ago, leaving his son the only candidate from the ruling party.
Ilham Aliyev's main rival, Isa Gambar of the opposition Musavat Party, obtained 12.6% of the vote, according to official results. The turnout was reportly just over 71% of the electorate.
Before the results were announced, he alleged widespread intimidation of voters, including people being threatened with the loss of their jobs, unless they voted for the 80-year-old president's son.
Gambar has alleged widespread intimidation
His supporters came out into the streets after polls closed, and began smashing cars and shop windows, once results were announced.
They clashed with riot police outside the Musavat party headquarters.
One man reportedly died of wounds sustained during a beating by police, while a child was believed to have been run over by an army truck commandeered by demonstrators.
Police dispersed protesters by charging with batons and using water cannon.