ROME — 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 today 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.

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.