Mongolia's opposition candidate was leading the country's first-ever presidential runoff election early on Saturday with more than three-quarters of votes counted.
Khaltmaa Battulga of the Democratic Party (DP), a 54-year-old former martial arts star, had 50.7 percent of the vote with 87 percent of ballots counted, the General Election Commission said.
"Mongolia has won," Battulga said at a press conference, though the commission will announce the winner later on Saturday. "I will start work straight away to resolve the economic difficulties and make Mongolians debt free as I promised."
Parliament speaker Mieygombo Enkhbold of the Mongolian People's Party (MPP), which holds the majority in the legislature, was behind with 41 percent.
Some 8.3 percent of the votes were blank ballots.
Many voters in the vast nation of three million people sandwiched between Russia and China were so fed up with their politicians that they launched a campaign to submit unmarked ballots.
A candidate must win more than 50 percent of the votes to be declared the winner. If neither candidate reaches this number, the parties are required to nominate different representatives for an entirely new election.
The country has been hit hard by a more than 50 percent fall in the price of copper, its main export, over the past five years, while slowing growth in China has hobbled the economy.
Battulga, a real estate tycoon whose company funded a massive $4.1m statue of emperor Genghis Khan, has pledged to tap the country's mining wealth to get Mongolians out of debt.
Al Jazeera's Adrian Brown, reporting from the Mongolian capital, Ulaanbaatar said the opposition candidate's promise of turning the economy around won him many voters.
"He won because he had a very simple message. He campaigned on a 'Mongolia first' platform and promised a tougher stance on China. He says he wants to have an equal relationship with Beijing," Brown said.
"He also promised to deal with the real issue worrying most people here right now - unemployment. Thousands of people in this vast landlocked country are mired in poverty."
The outgoing president, Tsakhia Elbegdorj of Battulga's Democratic Party, did not run because he served the maximum two four-year terms.