Greece was bracing for a new ballot on Monday, a day after national elections failed to deliver a single-party government, which vote-winner Prime Minister Kyriakos Mitsotakis' party poised to seek in order to govern alone.

Mitsotakis' conservative New Democracy party won a landslide victory in Sunday's election, with a comfortable 20-point advantage over its nearest challenger, Syriza, led by socialist Alexis Tsipras.

Conservatives received their highest performance since 2007, with voters praising the party for restoring economic stability to a country that was previously seen as an EU laggard.

But the win fell short of an outright majority, leaving Mitsotakis with two options: eyeing a coalition or calling for a new vote.

A divided country

On Monday, the left-wing newspaper Efsyn headlined "Shock and awe," a sentiment shared by both New Democracy and Syriza voters, while pro-government Proto Thema observed that the double-digit split was the country's biggest since 1974.

Mitsotakis himself said the "great victory surpassed our own expectations."

With the count almost complete, New Democracy won 146 seats in the 300-deputy parliament -- five seats short of a majority.

The 55-year-old Harvard graduate clarified, on Sunday, that his preferred option is calling for a new ballot.

Together we will fight as of tomorrow, so that in the next elections, what citizens have already decided -- a self-reliant New Democracy -- will be mathematically confirmed at the ballot."

"We will move forward, boldly and steadily, to complete today's important first step, and be the final winners," he said, adding that Greeks "want a strong government".

Tsipras also prepared for a new vote, now expected as early as June 25, saying, "The electoral cycle is not over yet."

The next battle, he said, will be "critical and final."

Interim Interior Minister Calliope Spanou is forecasted to formally announce the results at midday on Monday.

President Katerina Sakellaropoulou will then summon Mitsotakis and formally give him the mandate to seek coalitions in order to establish a coalition government, which the conservative leader has already said he will reject.

Similar mandates for Syriza and the third-placed socialist Pasok-Kinal are likewise doomed to failure, based on Sunday's results.

Sakellaropoulou is then required by the constitution to ask the five parties that made it to parliament on Sunday to work together to form a government.

If that fails, a senior judge will be chosen as temporary Prime Minister and new elections would be called.

The big picture

Former McKinsey consultant Mitsotakis, 55, led the country through the epidemic that ravaged Greece's crucial tourism economy during the previous four years.

Under his leadership, the former EU economic headache has had a post-Covid comeback, forecasting a 5.9%  growth in 2022.

Greece's prognosis was a far cry from the throes of the catastrophic financial crisis a decade ago, with unemployment and inflation receding and growth this year forecast to be twice that of the European Union average.

Mitsotakis' rule had been marred by a wiretapping scandal, as well as a February train catastrophe that killed 57 people.

The government first blamed the catastrophe, Greece's worst-ever train disaster, on human error, despite the fact that the country's infamously weak rail network had been underinvested for years.

Despite the large demonstrations that erupted in the aftermath of the rail catastrophe, Kostas Karamanlis, the transport minister at the time, was re-elected on Sunday. 

A new electoral rule that goes into effect in the next election allows the winner to get a bonus of up to 50 seats. Based on Sunday's results and that estimate, New Democracy is almost certain to win.

However, the left is expected to try to flip the trend by campaigning on the cost-of-living issues that many voters are concerned about.

Tsipras and the socialist Pasok-Kinal party, led by 44-year-old Nikos Androulakis, face an uphill battle.

Pasok picked up just 11.46 percent of the vote. 

Tsipras' former maverick finance minister Yanis Varoufakis, whose anti-austerity MeRA25 party failed to get enough support to enter parliament, was another victim on Sunday.

Read next: Greece President dissolves Parliament, schedules elections for May 21