Claudia Sheinbaum has been elected Mexico’s first woman president in the country’s 200-year history.
Mexico’s official electoral authority said preliminary results showed the 61-year-old former mayor of Mexico City winning between 58% and 60% of the vote in Sunday’s election.
That gives her a lead of about 30 percentage points over her main rival, businesswoman Xóchitl Gálvez.
Ms Sheinbaum will replace her mentor, outgoing President Andrés Manuel López Obrador, on 1 October.
Ms. Sheinbaum, a former energy scientist, has promised continuity, saying that she will continue to build on the “advances” made by Mr. López Obrador.
She also pledged to continue the outgoing president’s controversial “hugs not bullets” strategy of tackling crime at its roots.
Galvez had vowed a tougher approach to cartel-related violence, declaring “hugs for criminals are over.”
More than 450,000 people have been murdered and tens of thousands have gone missing since the government deployed the army to fight drug trafficking in 2006.
In her victory speech, she also highlighted what has set this Mexican election apart from previous ones. She told cheering voters: “For the first time in the 200 years of the [Mexican] Republic, I will become the first woman president of Mexico.”
But, she said, it was an achievement not just for her but for all women. “I’ve said it from the start, this is not just about me getting [to the top office], it’s about all of us getting here.”
She added: “I won’t fail you.”
Ms Sheinbaum also thanked her rival, Xóchitl Gálvez, who has conceded defeat.
Prior to running for president, Ms Sheinbaum was mayor of Mexico City, one of the most influential political positions in the country.