* Centre-right leader in pole position for Sunday election
* Former ultranationalist converted to EU integration
* Faces tough task to stabilise Serbia's shaky finances
By Matt Robinson and Jaksa Scekic
BELGRADE, March 13 (Reuters) - When state television captured Serbia's deputy prime minister wading into snowdrifts this winter to rescue a boy from a stranded car, it was one dramatic act too far for some sceptical Serbs.
Photo-shopped pictures of Aleksandar Vucic - dressed in superman underpants and cape, head superimposed onto the bulging green body of the Incredible Hulk, bare-chested astride a horse à la Vladimir Putin - went viral.
As with all good jokes, there was an element of truth. After 18 months in government, the leader of Serbia's dominant party has inspired the kind of idolatry, and amassed the kind of power, not matched since the late strongman Slobodan Milosevic.
The face of a government crusade against crime and corruption, Vucic is expected to lead his centre-right Serbian Progressive Party (SNS) to a resounding victory in a snap election on Sunday. Barring major upsets, he will become prime minister, with the task of overhauling Serbia's ailing economy.
The SNS is polling at more than 40 percent support. That's at least three times more than its closest rival, the opposition Democratic Party, and the kind of domination unseen since Serbia came in from the cold with Milosevic's overthrow in 2000.
If all goes to plan, Vucic's four-year mandate would take Serbia, the most populous country to emerge from the ashes of federal Yugoslavia, to within a few years of membership of the European Union. The irony is not lost on his detractors.
Until 2008, Vucic was a disciple of the "Greater Serbia" ideology that fuelled the wars of Yugoslavia's demise in the 1990s and left Serbia isolated and bankrupt.
He is haunted by YouTube, where in TV clips he rails against the West and heaps praise on genocide suspect Ratko Mladic, the accused architect of Europe's worst mass killing since the Nazis when his Bosnian Serb forces massacred 8,000 Muslim men and boys in Srebrenica in 1995.
Vucic broke with the ultranationalist Serbian Radical Party in 2008 and converted to the goal of EU integration as Serbia's best hope of recovery and prosperity.
Critics say the U-turn was motivated by little more than expediency, recognition that the ultranationalism of the 1990s was redundant in peacetime. Some are nervous of Vucic's power and popularity, in a country with an affinity for strongmen.
"Vucic has a firm hand, which obviously Serbs feel they need," said Marko Blagojevic of Belgrade-based pollster Centre for Free Elections and Democracy. "The situation is such that people are looking for authority."
The Serbian media have become increasingly cowed. Vucic served as information minister in the late 1990s when newspapers were fined or closed under tough legislation designed to muzzle dissent as Milosevic led Serbia into war with NATO over Kosovo.
"His slogan is 'Everyone for reforms', but until recently he was crying 'Everyone in uniform'," Democratic Party member Milivoj Vrebalov said on Wednesday, alluding to Vucic's sabre-rattling past. The Democrats, who came to power after Milosevic fell, have split in two since being shunted from office in 2012.
Vucic, a 44-year-old law graduate who worked in a London corner shop while learning English as a teenage student, readily admits he has made mistakes.
"But," he told a rally in the southern mainly Muslim town of Novi Pazar, "smart people learn something through life, and those who are not smart can live three lives and learn nothing."
Adopting the public manner of a well-groomed Western politician, Vucic has won over many of his harshest critics with his energy and apparent effectiveness in government.
His lead role in a much-publicised fight against crime and corruption, including the arrest and trial of influential Balkan retail tycoon Miroslav Miskovic, has increased his popularity.
But the outgoing coalition government he was part of since mid-2012 failed to produce the kind of far-reaching structural reforms that the International Monetary Fund says are needed to stabilise Serbia's shaky finances.
A bigger share of power would allow the SNS to jettison the likes of the Socialist Party of Prime Minister Ivica Dacic, which is hostile to pension reform, public sector pay cuts and steps to liberalise the labour market.
Serbia is wooing the IMF for a new precautionary loan deal, for which it will have to commit to cutting a budget deficit set at 4.6 percent of output for the year and stabilise public debt of more than 60 percent.
Serbian doctors have already protested over pay, and more such complaints may follow. Vucic says he won't be swayed.
"We can't spend more than we have," he told Serbian daily Vecernje Novosti. "Either we're going to pursue a realistic and rational policy, or we'll simply keep lying to ourselves." (Writing by Matt Robinson; Editing by Alistair Lyon)