According to Ixe Institute polls, Renzi is likely to secure 60 percent of the one million or so Italians who will vote for the Democratic Party (PD) leadership this Sunday, with neither of his rivals, Justice Minister Andrea Orlando and governor of the southern region of Puglia Michele Emiliano, likely to garner more than 15 percent of votes.

The vote will officially mark the reentry of Renzi into Italy's political arena after his humiliating referendum loss that prompted his resignation as prime minister last December.

Read: Italy's vote could spell years in the wilderness

And as Renzi gets set to make his political comeback with sights set on becoming prime minister in 2018, he has been clearly buoyed by Emmanuel Macron's result in the French first ballot, declaring that candidates "of renewal" and "in the center" are sure to win.

"In terms of policy positions and labor market reforms, it's true, Macron and Renzi are very similar," says political analyst Lorenzo De Sio. "But the big difference is Macron has been deliberately anti-populist. He's clearly stood for Europe and never allowed himself to use the populist language of [National Front] opponent Marine Le Pen. Renzi is the opposite."

Read: Former Italy PM Renzi calls for party reform, leadership contest

Breaking the mold

De Sio says Renzi's habit of speaking off the cuff, employing stale sound bites and railing against the privileges of politicians, makes him at times sound more like his fiercest rivals, members of the anti-establishment Five-Star Movement, than a mainstream party head.

Read: Is Italy's Five Star Movement the next blow to the establishment?

"He doesn't want to look like a politician," De Sio told DW, "but in marketing terms, if you cut the cost of a product, you're also cutting its value. If people perceive that politics has no value, they'll be more likely to vote for the Five-Star Movement," and not, he adds, the imitation of a populist.

Christine Vodovar, professor of Contemporary History at Luiss University in Rome, agrees it's a stretch for Renzi - a former prime minister, mayor of Rome and PD leader - to pass himself off as an outsider. But she says unlike Macron in France, Renzi actually has a strong base of followers.

"Only about half percent of people voted for Macron because of his ideas, the rest voted for him for strategic reasons," says Vodovar - in order to defeat left or far-right candidates.

"Renzi has more real followers, people who are voting for him because they believe in his program and his ideas," she told DW.

Difficult to beat

Yet even staunch Renzi supporters such as Democratic Party MP Sandro Gozi admits the Five-Star Movement - now slightly ahead of the PD in the polls at 30 percent - will be difficult to beat in an election.

"They take their votes from across the spectrum and have a range of positions. On immigration, they take an extreme-right position. On some economic issues, extreme left. And so far they've been immune to even their biggest failures like Rome Mayor Virginia Raggi," he told DW, referring to the Five-Star mayor and her ongoing troubles in cleaning up both the city streets and corruption.

Read: Rome mayor's scandal 'a catastrophe for the Five-Star Movement'

Yet it's not just the anti-establishment movement that could throw a wrench in Renzi's drive to return to power.

His own party and the relatively new American-style winner-takes-all way of electing party leaders introduced both in Italy and France could, too.

Macron, a career civil servant who served as economic adviser to outgoing Socialist Prime Minister Francois Hollande, sidestepped the snares of party politics by opting out of the Socialist Party primaries and refashioning himself as an independent.

Fighting for support

Renzi, on the other hand, decided to stake out his political terrain within Democratic Party. He defeated the traditional socialists in the 2013 primaries. As he plotted his return earlier this year, his most formidable opponents, fed up with what they see as Renzi's prima-donna style and neo-liberal economics, decided to leave the PD and formed a cluster of leftist splinter parties.

Lorenzo De Sio says major disagreements over economic reforms and policy still fester among those who have remained in the party. For decades, the Italian left held months-long consultations, where intricate deal-making ensured everyone felt invested in the leader and party.

However the primary system, first introduced in 2012, eliminated that, leaving supporters of a losing candidate feeling alienated.

"Elections are a classical way to force conflict to emerge and to determine a clear winner and loser," he says. "It's a flawed way to build consensus and in stark contrast to the party congresses that lasted for months in local branches, working their way to the convention, giving time and space for consensus building and accommodating different needs in the party."

Indeed, Renzi's opponents Orlando and Emiliano pushed for the convention to take place in the fall to allow for more consultation. It was an option Renzi rejected out of hand, fearing they'd gain more support.

But De Sio says it could pay for that choice later among left-leaning voters who no longer see themselves in the Democratic Party.

"When leader selection boils down to a power struggle between rivals without political confrontation or policy negotiation, it's not surprising the winner will not be that representative of the party."