Four days after Mexico held presidential elections, government candidate Claudia Sheinbaum has been officially declared the winner, making her the first female president in the country’s history.

A former mayor of Mexico City, Sheinbaum from the ruling left-wing Morena party won 59.75% of the votes, the electoral authority said late on Thursday.

Her main challenger, opposition candidate Xóchitl Gálvez, came in second with 27.45%.

Jorge Álvarez, from the smaller centre-left Movimiento Ciudadano party, had always been seen as having no chance.

Almost 100 million citizens were eligible to vote to fill all seats in the Chamber of Deputies and the Senate, as well as regional and municipal posts, making it an election day of historic proportions.

While the final results of the parliamentary vote are still pending, Sheinbaum’s Morena party is projected to have garnered a solid majority.

The party is hoping to secure a two-third majority in both chambers, to be able to single-handedly push through constitutional reforms, including the appointment of judges by direct vote, a plan that has critics fearing for the democratic separation of powers in Mexico.

Following the election, the Mexican stock exchange suffered losses and the peso, the national currency, lost around 5% of its value against the US dollar.

Sheinbaum is from the same party and a longtime ally of outgoing left-wing populist President Andrés Manuel López Obrador.

The popularity of the president, who was not allowed to run again after six years in office, helped the 61-year-old scientist to win the election.

Sheinbaum is expected to continue his policies, in particular the popular state aid schemes for young and old people.

Although the opposition conceded defeat, it intends to file a complaint with the electoral court about alleged irregularities in the electoral process, denouncing López Obrador’s undue interference and the use of state resources in favour of Sheinbaum.