Helen Clark will face her sixth Security Council ballot early tomorrow in her bid to become UN Secretary General but it will be the first one in which the permanent five will vote with a red ballot.
It will also be the first ballot in which Bulgaria's new candidate, European Union Commissioner Kristalina Georgieva, is a candidate.
Bulgaria has pulled support for its previous candidate, Unesco chief Irina Bokova, but Bokova is staying in the contest.
Any red ballot exercised will indicate a potential veto by any of the P5 countries: the United States, China, Russia, Britain and France.
It is expected that Clark will attract at least two vetoes, one from Russia which wants an Eastern European candidate, and one from France, which also wants an Eastern European.
Clark was mid field in the first ballot but as the field has shrunk with little movement in her support, she has slipped closer to the tail in relative terms.
In last week's ballot was second to last, equal, in a field of nine.
But Clark's strategy is to stay in the contest in the belief that the final outcome will be negotiated among the P5 and that she could be a compromise candidate.
But the former UN High Commissioner for Refugees and former Portuguese Prime Minister Antonio Guterres has been clear winner of the past five ballots, despite there being strong campaigns for the next Secretary General to be a woman and/or from Eastern Europe.
Slovakian Foreign Minister Miroslav Lajcak has also done well in the past three ballots, coming second, second and third.
Russia is chairing the Security Council in October and Russian ambassador Vitaly Churkin told reporters in New York this week that Russia believed it was "the turn" of Eastern Europe and added: "we would very much like to see a woman."
He also said there was a good chance that a few days after the ballot tomorrow, the council would formally pick a nominee to be presented to the UN general assembly for approval.
As well as the P5, the elected members of the Security Council comprise Angola, Egypt, Japan, Malaysia, New Zealand, Senegal, Spain, Ukraine, Uruguay, and Venezuela.