Now that his party has apparently won the support of his country's voters, Alexis Tsipras
has another fight in front of him: making good on his campaign promise to renegotiate the terms of Greece's bailout.
"We are regaining our lost dignity ... Now that we are heard by all of Europe, we will fight with the same passion, the same confidence," Tsipras told cheering supporters. "So let's go and let's all continue this beautiful and tough fight."
With more than 70% of votes counted, Syriza was officially projected to win at least 149 seats in the 300-seat Parliament.
Exit polls also placed the party in the lead. But analysts cautioned that it was still too close to call whether Syriza would win a majority of seats -- a key step that would allow the party to govern without forming a coalition government.
Tsipras, 40, who could become Greece's next prime minister, also vowed to end austerity measures.
"Greece leaves behind the austerity that ruined it, leaves behind the fear, leaves behind five years of humiliation, and Greece moves forward with optimism and hope and dignity," he told the crowd.
Syriza's pledges to try to get some of Greece's colossal debt written off and roll back unpopular austerity measures appealed to exasperated members of the electorate -- even if they potentially jeopardize Greece's place in the eurozone. The election could lead to a dramatic showdown with the debt-laden nation's lenders.
"That is a gamble that people in Greece seem to be prepared to take at this point, simply because the terms of its bailout have been so severe," Greek journalist Elinda Labropoulou told CNN on Sunday.
One of those people willing to take the risk is Eleni Antoniou, a former public sector employee.
"People went bankrupt since we entered the bailout, poverty is visible across society, and I believe that hope is coming with Syriza's program, not only for Greece, but for all of Europe," she said ahead of the election.
Outgoing prime minister: My conscience is clear
The austerity imposed by Greece's international creditors has cut deep
. Unemployment has soared to 28%, and many people who still have jobs have seen drastic decreases in wages, pensions frozen and the retirement age pushed back.
The governing New Democracy party had pointed to recent improvements in economic indicators as signs things were getting better.
After conceding defeat Sunday, outgoing Prime Minister Antonis Samaras said his conscience was clear.
"I got a country on the verge of ruin. I was asked to try and save it, and I did it," he said. "Most people did not believe we could stand strong, but we did."
Now, he said, Greece is secure and "slowly walking away from the crisis."
"And more than anything," he said, "I give back a country that is a member of the European parliament and the euro."
'Not the future of austerity'
In his victory speech Sunday, Tsipras noted that Greece's election could have an impact far beyond his country's borders.
"Our victory is, at the same time, it's a victory for all the people of Europe that are fighting against austerity that's ruining the common European future," he said.
His message is one that has resonated in other southern European countries under the restrictions of international bailouts.
Syriza's victory could boost other populist parties, like Beppe Grillo's anti-euro Five Star Movement in Italy and the Podemos Movement in Spain.
But it's unclear how its plans to renegotiate the bailout would play out.