Tsipras stuck to his guns, saying the political establishment wanted to lure in his party, the surprise runner-up in the elections a week earlier, as "partners in crime".
With the breakdown in talks it was uncertain whether the president, Carolos Papoulias, would summon the leaders again. The octogenarian head of state was due to meet the leaders of smaller parties, including the neo-fascist Chrysi Avgi, later on Sunday night.
The impasse arose after the mainstream New Democracy and Pasok parties were hammered at the ballot box for supporting the arduous terms of a debt relief deal drawn up by creditors to keep the heavily indebted economy afloat.
Instead, voters opted to support anti-austerity groups whose popularity has soared on the back of anger over cutbacks and reforms enforced in return for up to €240 billion (£193 billion) in aid. Chief among the winners was Syriza, which saw its ratings soar after promising a wholesale revision of the loan accord that Athens signed with foreign lenders.
On Sunday the new political demographic was on full display. As leaders entered the room for the talks, Tsipras assumed what some commentators described as a commanding position by choosing to sit to the left of the president, alone. Samaras and Venizelos sat opposite, exchanging strained smiles, as the much younger Tsipras bantered in front of the cameras.
The 38-year-old has much to be happy – and immovable – about. An opinion poll published on Sunday, seven days after Greece's electoral earthquake, suggested voters were bent on sending further tremors through the political landscape. The survey, conducted by Kappa Research for To Vima, showed support for Syriza climbing from 16.8% to 20.5%.
New Democracy would be projected to win 18.1% of a new vote, and Pasok 12.2%, their lowest ratings in the nearly 40 years that they have dominated Greek politics.
Emboldened by the ratings, Tsipras threw down the gauntlet, taunting his opponents to go ahead with the formation of a government. After all, he said, three parties – New Democracy, Pasok and the small pro-European Democratic Left – had agreed to form a government that would implement the unpopular policies, and with 168 Parliament members between them, they had a working majority.
"Those who for two years have governed us and are responsible for the situation of society and the economy have not only not got the message … they are continuing to blackmail and terrorize," he said in a statement after the talks.
"The three parties that have agreed with the goal of implementing the memorandum," he said, referring to the loan agreement, "have the majority. Let them go ahead. The demand that Syriza participate in their agreement is absurd. They are asking us to ignore the popular vote and our pre-elections pledges."
Highlighting the contradictions that have come to play in the unfolding Greek drama, an overwhelming 78.1% of Greeks said they wanted the new government to do whatever it took to retain the euro. The majority did not think Syriza's program was the solution to rescuing Greece from the crisis.
The negotiations follow a week of abortive attempts to form a coalition as each of the three party leaders – Samaras, Tsipras and Venizelos – took receipt of an "exploratory mandate" to try to create a government.
With anti-austerity rage clearly fueling the political dialogue, there is widespread consensus that, short of divine intervention, the president will fail in his attempts to broker a deal. He has until Thursday, when parliament is reconvened, to overcome the fault lines. If no headway is made, Greeks will return to the ballot box no later than 17 June.
Intellpuke: You can read this article by Guardian correspondent Helena Smith, reporting from Athens, Greece, in context here: www.guardian.co.uk/world/2012/may/13/greek-coalition-leftist-leader