Berlusconi's decision to hit the campaign trail to mobilise supporters appeared to have paid off to some extent, though his party's share of the vote was still down almost 11 points at 26.7 per cent compared to 37.4 per cent in the 2008 general election.
The PDL now stands less than one point ahead of the main opposition Democratic Party (PD), at 25.9 per cent, compared with a 4.2 point gap in 2008.
Pierluigi Bersani, the PD leader, said that while he was disappointed to lose photo-finishes in key regions, the vote still marked a positive "change of trend" for the opposition.
Analysts said the centre right's gains in terms of regions won, including an unexpected victory in Lazio, home to the capital, Rome, seemed to vindicate Giulio Tremonti's, Italy's economy minister, policies.
Tremonti has kept a tight rein on spending, avoiding the crises now facing many of Italy's Mediterranean neighbours.
"If the government had done badly there could have been a temptation to open the spending taps, but we can assume Italy will maintain its prudent spending stance," said Gilles Moec, an economist at Deutsche Bank in London.
The centre left, trounced by Berlusconi in the national election in 2008, and testing its fourth leader in two years, hung on to strongholds in central Italy and parts of the south.
At 64.2 per cent, turnout was down 8 points compared with the previous regional elections - a record low.
Raffaele Fitto, Italy's regional affairs minister, who had campaigned hard in his home region of Puglia in the southeast, tendered his resignation after the PDL candidate was defeated there.
Renato Brunetta, the civil service minister, who has enjoyed a high profile for his campaign to root out public sector shirkers, also suffered a personal setback when he failed in his bid to be elected mayor of Venice, his home town.
The Northern League, which campaigns for the north to stop paying for the less wealthy south, emerged as a clear winner, taking two regions for the first time.
The League has an ally in Tremonti, who on Tuesday repeated his pledge to devolve tax and spending powers to the regions.
The party won the northern region of Veneto as expected, becoming the biggest party there, but also edged ahead of the centre left in Piedmont and closed the gap with Berlusconi's PDL party in Lombardy, Italy's industrial heartland.
"The people want federalism, and we will give it to them quickly," said Umberto Bossi, the League's leader, promising to press ahead with reforms in the wealthy northern regions it now controls.
"The left no longer exists in the north," he said.
The League was one of the few parties that increased its share of the vote compared with the general election, rising sharply to 12.7 per cent from 8.3 per cent.
The party is now expected to press for more cabinet posts.
Many ordinary Italians, particularly from the south, raised alarm at the strong showing by the League, even in parts of central Italy.
"It is a really serious problem because it will divide Italy into two - we from the south will have to move to Spain!" said Paolo Pucci, a resident of Campania in southern Italy.