Rome, November 26 - Democratic Party (PD) leader Pier Luigi Bersani is set to take on Florence Mayor Matteo Renzi in a runoff in the primary to select the centre-left's premier candidate next weekend after none of the contenders won more than 50% in Sunday's first round. As expected Bersani, a 61-year-old former industry minister, was on course to finish top in the first round, with 44.9% of over three million votes cast, after most of the ballots had been counted on Monday. Renzi, a 37-year-old who presents himself as a modernizer, was second with 35.5%. The winner of the primary has a good chance of being Premier Mario Monti's successor as the PD are leading in the opinion polls ahead of next spring's national elections. "It's an excellent result," said Bersani, a veteran of Italy's former Communist party, the rump of which changed into a social democratic party after the fall of the Berlin wall before merging with the centrist Margherita (Daisy) party to form the PD in 2007. "It will extend the country's attention on us by a week and this will enable us to show who we are - a great progressive force that is able to help this country. "The result for me was enormously encouraging," he added later on Monday. "I'm very confident about next Sunday and I'm sure that the day after we'll all work together for the demanding gallop toward the elections". In the runoff Bersani is expected to benefit from the support of the third-placed candidate, Puglia governor Nichi Vendola. But Vendola, who is the leader of the Left, Ecology, Freedom party that is poised to run in coalition with the PD at next year's elections, did not give Bersani an immediate endorsement. "Pier Luigi Bersani has to earn the votes that I received in the first round," said the openly gay Vendola, who obtained 15.6% of the votes. "We will listen to Bersani and Vendola's words with meticulous attention and we'll orient our support accordingly". Unlike Vendola, Bersani and Renzi have both said they will continue the policies of Premier Mario Monti, whose emergency government has passed austerity measures to steer Italy away from the centre of the eurozone crisis, as well as structural economic reforms. The other two contenders in the first round of the primary finished some way behind the top three. Laura Puppato, a businesswoman and PD councillor in the Veneto regional assembly, and Bruno Tabacci, a member of the centrist Alliance for Italy party that is also set to run in coalition with the PD, won 2.6% and 1.4% of the vote respectively. The runoff candidates are set to take part in a TV debate on state broadcaster Rai on Wednesday, sources in Bersani's campaign said. Renzi, a slick performer with the media who is campaigning for Italy's political class to be rejuvenated and has been compared to the young Tony Blair, said he is hopeful of winning the primary despite coming second in the first round. "We'll try to beat Bersani and do it with fair play," said Renzi. "If he wins, then we'll help him. "The central issue is that we are starting again from scratch and we will play right up to the last minute. "We have to go and win over new people, who might have voted for Tabacci, Puppato or Vendola and who are ready to think and reflect regardless of the suggestions (given to them by the defeated candidates)". The fact that so many people voted in the first round of the primary was hailed as a big success for the centre left by the candidates and by political pundits. It was also seen as a good response to the growing tide of public skepticism about the country's political class as a whole. There is widespread disenchantment with the established parties, which have been hit by a series of scandals and have been discredited to some degree by having to call on Monti's technocrats to take over governing the country when the financial crisis risked spiralling out of control last year. This has helped comedian Beppe Grillo's anti-establishment Five Star Movement, which is against public funding of parties and wants a referendum on whether the euro should be Italy's currency, to climb to second place in the opinion polls behind the PD. Among the people to applaud the primary was ex-premier Silvio Berlusconi, who said the PD had served up a fine example of democracy, adding that he hoped Renzi would win. Berlusconi's People of Freedom (PdL) party is scheduled to have a primary of its own to choose its premier candidate on December 16, although this has been thrown into doubt by the ex-premier saying he was reconsidering his decision not to stand. PdL Secretary Angelino Alfano, who is one of six candidates set to run in the primary, has said the selection process will be redundant if Berlusconi decides to run for a fourth term as premier. The PdL, the biggest party in parliament at the moment, has dropped to third in the opinion polls after a series of corruption scandals hitting top centre-right politicians in Rome and Milan.