Claudia Sheinbaum has won a landslide victory to become Mexico's first female president.
She said on Sunday night (Monday morning in the UK) that her two competitors had called her and conceded her victory.
"I will become the first woman president of Mexico," Ms Sheinbaum said with a smile, speaking at a hotel in Mexico City shortly after electoral authorities announced a statistical sample showed she held an irreversible lead.
"We have demonstrated that Mexico is a democratic country with peaceful elections," she said.
Ms Sheinbaum, a climate scientist and former mayor of Mexico City, won the presidency with between 58.3 per cent and 60.7 per cent of the vote, according to a rapid sample count by Mexico's electoral authority. It was set to be the highest vote tally percentage in Mexico's democratic history.
Ms Steinbaum campaigned on continuing the political course that has been established over the last six years by her political mentor President Andres Manuel Lopez Obrador, whose popularity among the poor helped drive her triumph.
Victory for Sheinbaum is a major step for Mexico, a country known for its macho culture and home to the world's second biggest Roman Catholic population, which for years pushed more traditional values and roles for women.
She would be the first woman to win a general election in the United States, Mexico or Canada.
The 61-year-old led the campaign wire-to-wire despite a spirited challenge from opposition candidate Xochitl Galvez. This was the first time in Mexico that the two main opponents were women.
"Of course, I congratulate Claudia Sheinbaum with all my respect who ended up the winner by a wide margin," Mr Obrador said on Monday morning UK time, shortly after the National Electoral Institute announced her irreversible lead.
"She is going to be Mexico's first (woman) president in 200 years."
If the margin holds it would approach his landslide victory in 2018. Mr Obrador won the presidency after two unsuccessful tries with 53.2 per cent of the votes, in a three-way race where National Action took 22.3 per cent and the Institutional Revolutionary Party took 16.5 per cent.
Ms Sheinbaum is unlikely to enjoy the kind of unquestioning devotion that Mr Obrador has enjoyed.
She has vowed to improve security but has given few details and the election, the most violent in Mexico's modern history with 38 candidates murdered, has reinforced massive security problems. Many analysts say organised crime groups expanded and deepened their influence during Mr Obrador's term.
Persistent cartel violence and Mexico's middling economic performance appeared to be the main issues on voters' minds, with many expressing hopes Ms Sheinbaum would do more to help tackle crime and drug trafficking.
The elections were widely seen as a referendum on Mr Obrador, a populist who has expanded social programmes but largely failed to reduce cartel violence in Mexico.
His Morena party currently holds 23 of the 32 governorships and a simple majority of seats in both houses of Congress. Mexico's constitution prohibits the president's reelection.
Sheinbaum promised to continue all of Mr Obrador's policies, including a universal pension for the elderly and a program that pays youths to apprentice.
Mr Obrador claims to have reduced historically high homicide levels by 20 per cent since he took office in December 2018. But that is largely a claim based on a questionable reading of statistics. The real homicide rate appears to have declined by only about four per cent in six years.
Nearly 100 million people were registered to vote, but turnout appeared to be slightly lower than in past elections.
Voters were also electing governors in nine of the country's 32 states, and choosing candidates for both houses of Congress, thousands of mayorships and other local posts, in the biggest elections the nation has seen and ones that have been marked by violence.
