Newly elected governor of the wider Athens region Rena Dourou, who was backed by leftist Syriza party, waves to supporters in front of the University of Athens May 25, 2014.
Greek far-left opposition leader Alexis Tsipras declared victory over austerity policies on Monday as final results confirmed his anti-bailout party had won the country's election for the European Parliament.
Syriza's victory marked the first time a radical leftist party has won at the national level in modern Greece, although it fell short of the five percentage-point victory margin that could rattle the fragile ruling coalition government.
"This is a historic win," Syriza leader Alexis Tsipras told a crowd of cheering and flag-waving supporters in the early hours of Monday. "Today, the whole of Europe is talking about Greece because it condemned austerity."
Across the European Union, Eurosceptic parties of the far right and left made significant gains in the elections, their scores amplified by a low turnout.
With 95 percent of the vote counted in Greece, Syriza was on 26.5 percent, ahead of Samaras's New Democracy conservatives who took 22.8 percent, the interior ministry said.
The party also won the race for the governor of the greater Athens region, home to about a third of the population, bagging another prize in local election runoffs held simultaneously.
Syriza's Rena Dourou, who became the first far leftist to be elected governor of the greater Athens region, said Sunday's victory "was neither personal, nor the party's".
"This is a victory for the unemployed citizens, for the pensioners," she told Greek TV. "One could say this is a victory of David over Goliath".
Sunday's ballot was seen as a litmus test of support for Prime Minister Antonis Samaras, whose government has imposed hated wage and pension cuts at the behest of EU/IMF lenders bankrolling Greece since taking power in 2012.
Still, in a boost for the government, which backs a deeply unpopular EU/IMF bailout tied to austerity measures, the co-ruling Socialist PASOK defied predictions of a meltdown and secured 8.0 percent of the vote.
The coalition of New Democracy and PASOK combined won a bigger share of the vote than Syriza, which analysts said averted the possibility of early elections for now.
The Investment Bank of Greece said in a note that while it did not expect the election outcome to trigger early elections, the underlying mood was one of caution.
"Yesterday's election result should trouble all of us," Greece's leading conservative daily Kathimerini wrote. "The citizens expressed their discomfort over everything they have put up with over the last few years."
Syriza had sought to cast the EU vote as a referendum on Samaras's government, which in turn had urged Greeks to stick to the path of stability and promised the long-awaited recovery from a six-year recession was taking root.
The party, which shot from the political fringes to become the main opposition in 2012 on a fiercely anti-austerity message, has won much of its appeal from promising to reverse austerity in a country struggling through its deepest peacetime downturn.
© Thomson Reuters 2014