As the 69-year-old Berlusconi retreated to his Sardinian mansion for the Easter break, his most senior aide kept up a verbal attack on Mr Prodi, accusing him of throwing salt on Italy's post-electoral wounds by brushing aside his rival's offer of power-sharing talks.
"Silvio Berlusconi has shown he is ready to start a series of discussions. Yet all we've seen from Prodi are muscular responses," Paolo Bonaiuti said.
The supreme court is not expected to issue a final confirmation of Mr Prodi's victory until after the Easter weekend break, probably on Tuesday or Wednesday, when a recount of contested votes, demanded by Mr Berlusconi, is expected to be finalised.
"Italy is split right in two after last Sunday's vote," said Mr Bonaiuti, accusing Mr Prodi of attempting "a trial of strength".
"In this situation of deep division, what is Prodi doing? Instead of healing wounds, he's throwing salt on them," he added.
Mr Prodi, the 66-year-old former EU Commission president, told reporters nothing had changed.
"Enough. It's time to work. I am working calmly for a future government, and that's what we must do," said Mr Prodi, whose tiny 25,000-vote majority was just enough to win his disparate Union coalition a working majority in the 630-seat lower house of parliament. It also has a wafer-thin, two-seat majority in the Senate.
The closest election in living memory prompted Berlusconi's last-ditch appeal for a short-term, power-sharing government.
In an open letter to the Corriere della Sera daily, Mr Berlusconi proposed that rival coalitions forge a short-term agreement "to meet the country's immediate institutional, economic and international timetable".
Mr Prodi immediately dismissed the overture, instead demanding an apology from the conservative leader. "After what he said about vote-rigging, he should ask for forgiveness," he said.
Mr Prodi said he had "closed a chapter" and was now looking to the future.
"The country needs a breather, it needs to fly high, it needs joy, it needs to recuperate. Now we want to leave these (divisions) aside and begin to work for the country," he told journalists outside his home in Bologna.
Mr Berlusconi has kept up a steady barrage of invectives since Mr Prodi was declared winner on Tuesday, according to provisional results.
Citing irregularities, he demanded a re-check of what the interior ministry said were some 43,000 contested votes.
However, his battle to stay in power suffered a severe blow on Friday when it emerged that there were too few disputed votes to reverse the outcome of the election.
In a new twist to the election saga on Saturday, former reforms minister Roberto Calderoli said that more than 45,000 votes cast for a centre-left party in Lombardy, northern Italy, should be ruled illegal.
Mr Calderoli said the small Lega Alleanza Lombarda had registered its candidates in only one constituency, contravening Italy's new electoral law.