Italy's grassroots Five Star movement failed to reach the run-off in local elections held Sunday in four regional capitals - the northwest port city of Genoa, the cental city of L'Aquila in the Abruzzo, Catanzaro in Calabria and Palermo, Sicily.
The polls were a key test of parties' support ahead of national elections due by next May.
In Genoa, the Five Star movement's founder Beppe Grillo's hometown, the party's candidate Luca Pirondi took just 18.07 percent of votes, against 38.8 percent for centre-right candidate Marco Bucci and 33.39 percent for centre-left contender Giovanni Crivello, according to final interior ministry data.
In L'Aquila, Five Star candidate Fabrizio Righetti came fourth with a meagre 4.25 percent of votes, while centre-left contenders Americo Di Benedetto and Pierluigi Biondi were set to advance to the run-off with 47.8 percent and 35.54 percent of ballots respectively, according to partial interior ministry data.
Centre-right candidate Sergio Abramo and centre-left contender Vincenzo Antonio Ciconte were poised to enter the run-off in Catanzaro with 39.08 percent and 31.25 percent of votes while the Five Star's Laura Bianca Granato came fourth with 5.66 percent of ballots, according to partial interior ministry data.
In Palermo, where the threshhold for victory is 40 percent, incumbent centre-left mayor Leoluca Orlandi appeared the winner with 45.71 percent of votes counted at 204 out of 600 polling stations. Five Star candidate Ugo Forello was in third place with 15.9 percent of ballots.
In the northern city of Parma, incumbent mayor Federico Pizzarotti - a former Five Star party member standing for re-election as an independent - will face centre-left candidate Paolo Scarpa in the run-off after they polled 34.78 percent and 32.73 percent of votes respectively, final interior ministry data showed.
Centre-left and centre-right candidates took the biggest share of votes and Five Star performed poorly in almost all of the 1,004 town halls up for election across the country on Sunday representing over nine million Italians.
The failure to advance to the second round in any of the mayor races in the regional capitals is a sharp setback for Grillo's party, which opinion polls have suggested is neck-and-neck with the ruling centre-left Democratic Party nationwide.
"This is a huge defeat for Five Star," said the Democratic Party's local affairs chief Matteo Ricci. "Not only are they not making the run-offs, but they are polling disastrous numbers."
Five Star won mayor races in the Italian capital Rome and in the northwest industrial city of Turin last year after taking 25 percent of votes in the 2013 national elections, but in-fighting and scandals have dented its support.
Prosecutors put Rome mayor Virginia Raggi under investigation earlier this year for abuse of office and false testimony and her administration has come under attack for failing to fulfil key electoral pledges such as solving the chronic garbage collection problem in Rome.
Raggi denies wrongdoing as Rome's mayor and in March denied any "irregularities" with the signatures gathered for her electoral list last year as alleged by an Italian investigative TV show.
The report by Le Iene programme on ex-premier Silvio Bersluconi's Italia 1 channel was based on claims made by Alessandro Onorato, a Rome city councillor elected on a list that backed one of Raggi's rivals in the mayoral race, billionaire businessman Alfio Marchini.
