Tsipras sworn in as Greek PM

If there was doubt in the rest of the eurozone about the strength of Tsipras’ anti-bailout rhetoric, he sought to put it to rest by indicating he will form a coalition with the Independent Greeks, a small populist right-wing party with little in common with Syriza except a hardline anti-austerity stance.

Syriza won 149 seats in the 300-seat parliament, two short to have an outright majority. The Independent Greeks won 13 seats.

Yanis Varoufakis, who is tipped to be finance minister, said Syriza had inherited a “poisoned chalice”.

He told BBC radio that Greece’s bailout repayments should be bound to its “recovery, not to our misery".

Other governments have, on the whole, reacted cautiously to the completely new political landscape in Greece, and the likely tough negotiations that are to follow with international creditors.

Berlin said it would work with the new government but emphasised that Greece should "respect" its committments.

Finnish PM Alex Stubb said Finns will “not accept a demand for debt cancellation”, while British leader David Cameron said he respects the Greek peoples' decision but that the country must deal with its debts.

The International Monetary Fund, one of Greece international creditors, took a tough line immediately.

Christine Legarde, IMF chief, told Le Monde that: "We cannot make special categories for such or such country".

She also called on Tsipras to tackle the judicial system and tax-collection, noting that this is not austerity but a matter of structural reforms.

Where to next?

While Tsipras initially took a much stronger line on what to do with the country's crippling debt - 175 percent of GDP - he moderated his language in recent weeks as a Syriza victory became more likely.

Greece has been given some concessions in the past, including extending the maturity of the debt and cutting the interest rate.

But ordinary Greeks have not felt any difference, amid tax hikes, wage cuts, and public service cuts that have pushed millions into poverty and seen the unemployment rate among the young shoot up to around 50 percent.

Meanwhile, Eurogroup chief Jeroen Dijsselbloem warned that there is little support for writing off Greece's debt.

"Writing off debt in nominal value? I don't think there is a lot of support for that in the Eurozone," he said ahead of a meeting of euro ministers on Monday evening.

But although the Greek government is taking shape with lightning speed, euro partners are waiting to see what the realities of being in power and working with the compromise-laden eurozone will mean in practice.

"We are not going to enter into the [negotiating] details today," said EU economic affairs commissioner Pierre Moscovici.

He said Monday's eurogroup meeting has to "give a strong signal that we want to start discussing with the new government".