Populist billionaire Andrej Babis and his ANO movement decisively won the Czech Republic's election on Saturday in a vote that shifted the country to the right.
The results paved the way for the Eurosceptic to lead the country, as with votes from 99.6% of all polling stations counted by the Czech Statistics Office, ANO had 29.7%.
Since the president usually asks the leader of the strongest party in parliament's lower house to try to form a new government, Mr Babis could be the country's next prime minister despite allegations of fraud linked to European Union subsidies and other scandals.
That would produce another Eurosceptic government in Central Europe.
In a blow to the country's traditional political elite, four of the top five vote-getting parties on Saturday were ones that have challenged the traditional political mainstream.
Some exploit fears of immigration and Islam and have been attacking the country's memberships of the EU and Nato.
According to the results, the opposition conservative Civic Democrats came in a distant second, with 11.3% of the vote, the strongest mainstream party.
The Social Democrats, the senior party in the outgoing government that won the 2013 election, had only 7.7% of the vote.
The Pirate Party won seats for the first time, coming in third with 10.8% of the vote while the most radical anti-migration, anti-Muslim, anti-EU party, the Freedom and Direct Democracy, was in fourth place with 10.7%.
ANO is united with most other Czech parties in rejecting the EU's quota system on redistributing refugees.
Mr Babis has been critical of the EU and opposes setting a date for the Czech Republic to adopt the euro.
A record nine parties and groupings made it into parliament amid the comprehensive defeat of mainstream parties.
"It's a voting hurricane," analyst Michal Klima told the Czech television, referring to the results for mainstream parties.