With the clock ticking to pull Italy back from the brink of a full-blown debt crisis, the nation turned Sunday to a clinical-minded economist to take the reins of power after the resignation of its longtime playboy prime minister, Silvio Berlusconi.

Mario Monti, a 68-year-old former university president and European Commission member, was named interim prime minister, effectively charging him with the task of bringing Italy’s bickering political parties together behind a new transitional government.

But only hours after Berlusconi stepped down, his still-powerful party was holding out for tough conditions to support Monti in the days ahead, and the 75-year-old media tycoon was already hinting at an eventual comeback attempt.

On Sunday, just as Monti’s post was being made official by President Giorgio Napolitano, Italy’s ceremonial head of state, Berlusconi unleashed a limelight-stealing video message to the nation calling his resignation Saturday an act of personal selflessness and vowing to work tirelessly to “save Italy.”

With markets opening Monday for the first time since Berlusconi’s resignation, the lingering political uncertainty here suggested nail-biting days ahead. In addition, analysts said that even if Italian politicians coalesce behind Monti’s interim government, it remains unclear whether his mandate will be strong enough to push through a package of economic measures that economists say is needed to restore investor confidence in the world’s eighth-largest economy.

“Italy can overcome this crisis together,” Monti said from Rome’s Quirinal Palace, adding that he would urgently seek to form a new government. “We owe it to our children, so that they may have a future of dignity and hope.”

For now, at least, the challenge of trying to save Italy was in the hands of Monti, a technocrat who in many respects is the anti-Berlusconi.

Berlusconi’s resignation came after he denied the existence of a crisis, losing the confidence of investors, other European leaders and his political allies. In contrast, Monti, who has been nicknamed “Super Mario” for his skill as a European commissioner, is well respected in Europe’s boardrooms and halls of power. He also is viewed as a credible figure who has spoken widely about the need for Italy to introduce more competition and take other major steps to ignite an economy that has wallowed in low to negative growth for years.

Monti was selected specifically because he appeared to have no long-term political ambitions and was not beholden to any of Italy’s big party bosses. But his reputation as an outsider in the personality-driven world of Italian politics was both a help and a hindrance as he sought to form a new government. Some of the measures under consideration to reassure investors — including a levy on property and bank accounts — could be so politically difficult that he would require strong backing in parliament.

“On one hand, he is well known in Europe, and the markets like Monti,” said Gianfranco Pasquino, a political scientist at the University of Bologna. “But on the other hand, he is very new to Italian politics, which is basically a lake of sharks.”

Though a free-market economist, Monti was nevertheless facing the fiercest resistance from Italy’s right wing. The conservative Northern League has refused to back him, instead calling for snap elections that could leave the nation stuck in a political vacuum for months.

That made support from Berlusconi’s People of Liberty Party central to Monti’s ability to govern. On Sunday, the party’s chief and Berlusconi’s anointed successor, 41-year-old former justice minister Angelino Alfano, said the party would back Monti only if a list of conditions was met. They included a pledge that the term and mandate of the new government would be strictly limited to passing the needed package of economic measures, after which new elections would be held. The party also wants the right to approve Monti’s new list of ministers and insists that only technocrats — not political figures — make up the new cabinet.

Yet Alfano also said that Berlusconi, who dominated Italian politics for nearly two decades and whose womanizing and corruption charges divided the nation, was not yet ready to “walk in the gardens” of political retirement. Berlusconi drove that home Sunday, issuing a letter to a right-wing party suggesting he hoped to “resume the path to government.” He also issued a lengthy, after-the-fact resignation speech, taking a swipe at the protesters who chanted “fool” at him and uncorked champagne to celebrate his downfall Saturday night.

“To those who yesterday exulted for my exit from the political scene, I say very clearly that starting tomorrow, I will double my efforts in parliament to renew Italy,” Berlusconi said.

Special correspondent Sarah Delaney contributed to this report.