Europe’s leftist parties and their supporters are cheering Monday.

Just hours after claiming victory in national elections, Alexis Tsipras, head of the leftist Syriza party and the new Prime Minister-elect of Greece, has agreed to form a coalition government and repeated his vows to push swiftly ahead with the promised economic reforms that fueled his party’s historic win.

Tsipras was formally sworn-in as Prime Minister in Athens on Monday afternoon. “We have an uphill road ahead,” Tsipras told President Karolos Papoulias just before the ceremony.

Failing to win an outright majority in Parliament, winning 149 seats of the 151 needed, Tsipras earlier on Monday held a meeting with Panos Kammenos, leader of the Greek Independent party. Following their discussion, Kammenos emerged and confirmed the coalition. According to media reports, Kammenos said, “The Independent Greeks give our vote of confidence to the prime minister, Alexis Tsipras.”

“I want to say, simply, that from this moment, there is a government,” Kammenos added. “The prime minister will go to the president and … the cabinet makeup will be announced by the prime minister. The aim for all Greeks is to embark on a new day, with full sovereignty.”

Known as a center-right party that espouses a virulent populism and a shared disgust towards the austerity imposed from without, the Greek Independents took approximately 4.7 percent of the national vote and their seats will allow Syriza to rule without bowing to other rival parties. As the Washington Post notes, the two parties “have virtually nothing in common beyond their shared antipathy for the stringent terms of the country’s $284 billion bailouts.”

Though the reactions from across Europe were predictably mixed, progressives from all quarters were found celebrating Syriza’s impressive showing at the polls.

“The result of the Greek election is a resounding rejection of the austerity policies that have had devastating economic and social consequences,” said Costas Panayotakis, professor of sociology at the New York City College of Technology of the City University of New York. “Having received over 35 percent of the vote, Syriza, Greece’s leading party of the anti-austerity left, is poised to form a government in coalition with a smaller party of the anti-austerity right and to challenge the austerity policies imposed throughout the eurozone. In so doing, the Greek election could prove an important turning point, further fueling the rise of anti-austerity forces of the left in Spain, Ireland and beyond.”

Nobel Prize-winning economist Paul Krugman called the election results a “political earthquake” for Europe as he expressed hope it would help end the “nightmare” of austerity for the Greek people. He also urged Syriza to ignore those calling for the party to scale back its plan to re-negotiate the terms of its economic relationship with the so-called Troika—the IMF, the European Commission, and the European Central Bank.

According to Krugman:

Reuters reports:

The idea that Syriza’s victory in Greece would create opportunity for other leftist parties on the continent was widely shared.

“The Greek people have clearly rejected the EU’s neoliberal economic experiments,” said Pernille Skipper, a policymaker and spokesperson for Green-Red Alliance in Denmark. “The Greeks have said no, that ordinary people should not have to foot the bill for the financial crisis. It should inspire people in other European countries.”

In Spain, Pablo Iglesias, a vocal ally of Tsipras and head of the nascent leftist Podemos Party, said the victory for Syriza in Greece portends more victories for those calling for a social and economic re-ordering. “Hope is coming, fear is fleeing,” he said of the shift in Greece. “We are hoping we will hear the same thing in Spain soon.”

And in France, Jean-Luc Melenchon, perhaps the nation’s most prominent far-left politician described his response to Syriza’s win as “pure happiness.”

“This is a new page for Europe. Maybe we can take the opportunity to rebuild Europe, which has become the federal Europe of the liberals,” Mélenchon told BFM TV. “The Greeks are trying to break out of this straight jacket and thanks to them, maybe we will be able to lay out all the figures on the table, that has made life hellish in Europe.”