Berlusconi was the last Italian Prime Minister to win an election, back in 2008. Renzi will be the third leader in a row appointed by Napolitano. By being at the centre of electoral reform negotiations, Berlusconi will do his best to ensure a system that gives some advantage to his centre-right party.
One key meeting for Renzi was with Angelino Alfano, Interior Minister and leader of the New Centre-Right Party - a minor partner in the coalition whose support will be important for a Renzi-led government. But Renzi's real battles will be with Berlusconi and the populist Five Star Movement (5SM) of rabble-rousing ex-comedian Beppe Grillo.
The left-wing daily Il Fatto Quotidiano quoted one of Renzi's inner circle as saying his primary objective in his first 100 days would be "to bury" the anti-establishment 5SM, which a year ago won 25 per cent of the vote.
Already Grillo - who does not have a parliamentary seat - has dismissed Renzi as "a careerist without scruples". The M5S has boycotted the consultation process at the presidential palace and says it will not co-operate with a Renzi government.
Giuseppe Orsina, professor of political science at Luiss University in Rome, says Renzi faces huge risks by assuming power in this way. But according to the source close to Renzi, quoted in Il Fatto: "If there's a thing that excites Matteo it's the word 'risk'. There'll be lots of fireworks." Independent