Andrzej Duda (R), presidential candidate of the right-wing opposition party Law and Justice (PiS), celebrates after exit poll results are announced in Warsaw, on May 24, 2015
Warsaw (AFP) - Polish voters have opted for change and chosen the conservative and relatively unknown lawyer Andrzej Duda as their next president, spelling a possible return to power of his eurosceptic mentor in autumn parliamentary elections.
The opposition challenger clinched surprise victory in a Sunday run-off against incumbent centrist Bronislaw Komorowski, who is allied with the governing Civic Platform (PO) party and until recently was expected to secure a second term.
An MEP with a populist streak who promised change and generous social spending, Duda scored 51.55 percent support ahead of Komorowski's 48.45 percent, according to final results from the election commission Monday.
The result gives a key indicator of the national mood ahead of a general election expected in late September or early October that analysts say could return Duda's conservative Law and Justice (PiS) party to power after eight years.
PiS leader and Duda mentor Jaroslaw Kaczynski -- a populist ex-premier and twin brother of the late president Lech Kaczynski -- will be the party's candidate for premier, several PiS officials said Monday.
The 43-year-old Duda will take up his new office on August 6 and enter into what is expected to be a difficult cohabitation with the PO government of Prime Minister Ewa Kopacz in the Central European heavyweight.
- Congratulations from Putin -
Political scientist Radoslaw Markowski believes Duda's victory surprised the party itself.
"Their problem now will be to maintain his image as a president of all Poles, given that he was elected mainly thanks to a rural and poorly educated electorate," he said.
The governing liberals were also to blame for the outcome in the EU member nation, according to political analyst Eryk Mistewicz.
"Over the course of eight years, the PO built up a system that is closed off to youths, where upward mobility is impossible."
The PiS is nationalist and eurosceptic and agrees with the country's powerful Roman Catholic church on issues including abortion.
The Church congratulated the devout Duda, who on Monday visited the Jasna Gora monastery in the southern city of Czestochowa to offer "thanks for the support". The monastery is home to the Black Madonna, an ancient Catholic icon of the Virgin Mary that is believed to work miracles.
Kaczynski gained a reputation for being highly combative and eurosceptic during his 2006-7 stint as prime minister, when he served in tandem with his late twin, who died in a 2010 plane crash in Russia.
Russian President Vladimir Putin on Monday congratulated Duda and called for "the building of constructive ties between Russia and Poland, based on the principles of good neighbourly relations and a mutual respect for each other's interests".
The two countries' historically complicated ties are in the doldrums as Poland has been one of the fiercest critics of Soviet-era master Russia over its alleged meddling in Ukraine.
Duda has called for NATO to station its troops on Polish soil. As president, he will have limited powers but is commander-in-chief of the armed forces, steers foreign policy and has the right to introduce and veto legislation.
His first state visit abroad will be to Brussels, then Kiev, according to PiS member and European Parliament Vice-President Ryszard Czarnecki.
- Coffee for the people -
At home, Duda could try to block a draft law that would make in vitro fertilisation (IVF) reimbursable.
The economy could be the biggest minefield for Duda, who believes Poland should only enter the eurozone once the European single currency has solved all its debt woes.
He has promised to lower the retirement age from 67 to 65 years and cut taxes for those earning the least while upping taxes for supermarket chains and banks.
But lowering taxes is "unfeasible" according to Witold Orlowski, chief economist at PriceWaterhouseCoopers Polska.
Duda crisscrossed the country throughout the campaign wooing the man on the street, always full of energy, his sleeves rolled up and a broad smile on his face.
In keeping with his man-of-the-people image, Duda appeared on Monday at a Warsaw subway station and gave out free coffee to passers-by. He also announced that he would give up PiS membership as Polish presidents are supposed to remain neutral.
The country of 38 million people has avoided recession over the last quarter of a century.
The economy is set to expand by 3.5 percent this year, but joblessness is still high and stood at 11.3 percent in April.
"Poles want change. They issued a yellow card to the PO and risk issuing the party a red card at the general election," wrote Poland's Polska The Times daily on Monday.
Voter turnout was high on Sunday at 55 percent.