MEXICO’S most populous state turned its back on decades of single-party rule, deciding to move forward with President Andres Manuel Lopez Obrador’s ruling Morena party over the long-dominant Institutional Revolutionary Party (PRI).

Results from electoral authorities on Sunday night indicated a victory for Delfina Gomez in the State of Mexico that was confirmed a short time later by Alejandra del Moral’s concession speech. 

The result was a new low for the PRI, which governed Mexico uninterrupted for 71 years until losing power in 2000 and had ruled the State of Mexico for even longer until its loss Sunday.

A representative sampling of voting stations just hours after polls closed indicated Ms Gomez was likely to win between 52.1 per cent and 54.2 per cent of the ballots, compared with 43 per cent to 45.2 per cent for Ms del Moral, according to the National Electoral Institute. 

“There is going to be a different governance,” Ms Gomez said late on Sunday night before cheering supporters in the state capital of Toluca. 

The state’s first female governor elect stressed her commitment to the mothers of missing people and victims of femicide, and called for the public to denounce corruption.

However, the PRI-led coalition appears to have held onto the governorship in the sparsely populated northern border state of Coahuila.

At the time of writing, with most votes counted, the PRI coalition candidate Manolo Jimenez led by a massive 35 points over the Morena challenger.

But losing the State of Mexico was a heavy blow to the political fortunes of the PRI.

The contest was closely watched, too, because of its potential implications for next year’s presidential elections. 

Even without having selected its nominee yet, Morena is considered the frontrunner in that national election, more so now with control of the State of Mexico.

The State of Mexico hugs Mexico City on three sides, encompassing urban sprawl and rural ranches, as well as stunning inequality, violence and corruption. 

For decades it has been the heart of the PRI.

The loss of the State of Mexico is a stunning reversal for a party that ruled Mexico uninterrupted for seven decades even though turnout was only about half of eligible voters in the State of Mexico.

Adair Ortiz Herrera, an information systems student from Coyotepec, a rural area in the northern part of the state, said before the results were announced Sunday that he was sure “a new direction” was coming.