"I am glad about that horrific democratic slap in the face that the Greek people have just handed the European Union," President of France’s National Front party Marine Le Pen writes on her Twitter page.
However, apart from their mutual opposition to austerity, the two parties disagree on practically every other issue.
The centrist Potami (river) party was battling for third place with the Nazi-inspired Golden Dawn, whose leader and several lawmakers campaigned from prison, where they are awaiting trial on charges of participating in a criminal organization
Prime Minister Samaras conceded defeat later on Sunday.
Greek voters have long been unhappy about the austerity program imposed by Brussels and Berlin in return for loans to fund the country’s massive debt.
The Syriza party pledges to scrap the politically-destructive belt-tightening loans program, pointing to a six-year-old economic slowdown.