A conservative provincial mayor has been chosen to face off against Hungarian Prime Minister Viktor Orban in next year’s election.
Peter Marki-Zay, a political outsider with no party affiliation, won an opposition run-off primary on Sunday.
He will now lead a united opposition into the parliamentary elections.
Opinion polls suggest he has the best chance of ousting the right-wing prime minister, whose Fidesz party took office in 2010.
“We want a new, cleaner, honest Hungary, not just to replace Orban or his party,” Mr Marki-Zay told jubilant supporters in Budapest.
Mr Marki-Zay, 49, a practising Catholic and father of seven, was 20 points ahead with around half the votes counted when his centre-left opponent Klara Dobrev congratulated him on his victory.
“From now on I support Peter Marki-Zay,” Ms Dobrev said during a concession speech, urging opposition unity after a bruising election campaign.
For years Fidesz has benefited from the fragmentation of opposition parties.
But for the first time since he came to power, Mr Orban will now face a united front of opposition parties that also includes the socialists, liberals and the formerly far-right, now centre-right, Jobbik.
Mr Marki-Zay has sold himself as a palatable option for voters from the left and right, including those tired of Mr Orban’s often divisive policies, such as anti-immigration and anti-LGBTQ drives.
The new opposition leader, who has lived in both the US and Canada, made a name for himself in 2018 when he won the mayoral election in the southern town of Hodmezovasarhely, which was considered a Fidesz stronghold.
“We want to get rid of the big boys bullying the whole class,” Mr Marki-Zay said at the time.
But there is a long road ahead for Mr Marki-Zay, who has vowed to stamp out corruption and heal divisions in society. Polls suggest there is little between Fidesz and the opposition alliance.
In a statement, Fidesz said their rival had signed a pact with the political left to help them return to power, and raise taxes, labelling him a “career leftist”.