Despite record results in France's first round of regional elections, opinion polls on Thursday showed the key figures of the far-right National Front (FN) were on track for defeat.
The two-stage election system in France has often worked against the anti-immigration FN, as traditional parties team up for the second round to keep it out of power.
That could play out again on Sunday, with voter surveys showing that FN leader Marine Le Pen and her 26-year-old niece Marion Marechal-Le Pen are likely to lose in their respective regions despite dominating the first round.
Both Marine in the economically depressed Nord-Pas-de-Calais-Picardie in the north, and Marion in the southern Provence-Alpes-Cote-d'Azur took over 40 percent of the vote last Sunday in an unprecedented result for the party.
Marine Le Pen was in thundering campaign mode on Thursday, telling supporters in Calais that, if elected, "I will make the government's life a misery, do you hear me? Every day, every week."
But a poll by the TNS-Sofres institute and the LCI TV channel showed her being beaten by Xavier Bertrand of the centre-right Republicans in the north, by 53 percent to 47 percent.
The same poll indicated the Republicans' candidate in the south, Christian Estrosi, would score a clear victory over Marechal-Le Pen by 54 percent to 46 percent.
The Republicans of former president Nicolas Sarkozy have been helped by the fact that the ruling Socialist Party, which came a distant third in both regions, has dropped out of those races as a deliberate strategy to keep the FN from power.
Many supporters of smaller parties will also flock to the Republicans out of disgust with the FN, whose hyper-nationalist agenda has exploited concerns over immigration and terrorism in the wake of last month's attacks in Paris.
"They are two very difficult contests," admitted a senior FN leader, speaking on condition of anonymity.
"It's still in play, but faced with the right-wing, it's difficult."
The same problem hit the FN during local elections in March, when the party found itself facing off against the Republicans in 538 localities in the second round, and lost 535 of them.
The far-right's best hopes may even lie in the eastern Alsace-Lorraine-Champagne-Ardenne region, where its list is led by the somewhat unlikely figure of Florian Philippot.
The FN vice-president is gay, and the product of an expensive education at one of France's "grande ecoles" -- hardly the obvious qualifications for a socially conservative party built on a resolute hatred of the elitist political cabal in Paris.
Philippot's status reflects the changes in the party since Marine Le Pen took over from her rabble-rousing father, Jean-Marie Le Pen, in 2011 and sought to broaden the party's appeal.
Marion Marechal-Le Pen, who turned 26 on Thursday, is seen as closer to the party's old guard. She marched against gay marriage in 2013 and opposes support for family-planning associations on the grounds that they are "peddling abortion".
Philippot was only slightly less dominant than the two Le Pens in the first round, taking 36 percent of the vote, 10 points ahead of the Republicans' candidate.
But his main advantage is that Socialist candidate Jean-Pierre Masseret, who came a distant third, has refused orders from his bosses to throw in the towel.
The FN still has several chances of taking control of its first-ever region, having topped first-round voting in six of 13 areas.
Since the party took the highest share of the nationwide vote last week on 28 percent, Marine Le Pen said voters would be furious if it is once again left empty-handed on Sunday, threatening that they would take their "revenge" when she runs for the presidency in 2017.