"We're not crying victory, but we're very, very confident," a senior Mexican diplomatic source as the Geneva-based World Trade Organization prepared to wrap up the contest pitting Blanco against Brazil's Roberto Azevedo.
"It wouldn't be responsible today to talk about the number of votes," the source added.
Frenchman Pascal Lamy, a former European Union trade chief, bows out on September 1 after two four-year terms as director general of the WTO.
With little to separate the candidates in terms of vision for breaking the deadlock in the 159-member WTO's "Doha Round" negotiations, the diplomatic guessing game is mounting.
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The Doha Round, launched at a summit in Qatar in 2001, aims to open markets and remove trade barriers such as subsidies, excessive taxes and regulations, in order to harness international commerce to develop poorer economies.
"We've got support from all countries, whether least-developed, developing or developed, and from all regions," the Mexican source said.
Blanco, a 62-year-old economist, has a heavyweight reputation.
He was Mexico's negotiator for the 1994 North American Free Trade Agreement, served as a minister of commerce and also boasts solid private sector credentials.
"He's someone who generates a vast consensus among member countries, and inspires confidence in the business world," the source said.
But 55-year-old Azevedo could benefit from his insider status.
Like Mexico, Brazil repeatedly has flagged up its candidate's broad support across nations and economic levels.
According to the Brazilian newspaper Estado, the government's diplomatic soundings put Azevedo's support at some 106 of the 159 WTO nations.
EU member states were reportedly split, with Portugal, Spain, Italy and France pro-Azevedo, and Britain backing Blanco.