GENEVA — Brazil’s ambassador to the World Trade Organization, Roberto Azevedo, won the race Tuesday to head the global agency that oversees most international commerce, after the third and final round of polling, defeating former Mexican minister of trade and industry Herminio Blanco.

Azevedo, 55, is viewed as a skillful diplomat and a consensus builder. His foremost task will be to rebuild trust in the global body, which has failed for years to break the stalemate in the troubled Doha Round of trade liberalization talks.

The Brazilian made his reputation by successfully leading his country’s international legal challenge of U.S. cotton support measures, which WTO dispute panels ruled breached global rules.

His selection to the director-general post is expected to be recommended in a WTO closed-door meeting Wednesday and to be given the green light, if no snags emerge, on May 14 by the agency’s ruling general council, diplomatic sources said.

Azevedo’s move to the top WTO post, secured by strong support from major emerging powers, is also expected to encourage poor African cotton exporting nations to revive their longtime campaign to get rich countries such as the U.S. to scrap what they see as trade distorting subsidies in the sector.

“Even though WTO director-generals have their hands tied and they have to respond to the will of the membership, they also have the possibility of putting their initiative in front to resolve issues,” said Ricardo Meléndez, chief executive officer of the Geneva-based International Center for Trade and Sustainable Development. “The case of cotton is a typical case where some initiative may get us out of this mess.”

Trade experts anticipate it will also encourage poor developing nations to push to be granted duty-free and quota-free access for 97 percent of tariff lines, including textiles and apparel, if a global trade accord is revived.

Meléndez, a former Colombian trade diplomat and chief textile negotiator for his country, said he expects Azevedo to be “nondogmatic” on trade liberalization matters.

He said it’s also quite possible that Azevedo, who campaigned as an independent WTO director-general, could be instrumental from his new post to influence the Brazilian government to put a stop to its protectionist drift.

Pascal Lamy, the incumbent WTO chief, is slated to step down from the post on Aug. 31.