CHATTANOOGA, Tennessee (Reuters) -Workers at Volkswagen's Tennessee plant have voted to join the United Auto Workers, in a seismic victory for the union as it drives beyond its Detroit base into the U.S. South and West.

A majority of eligible workers cast ballots in favor of the union, with the final tally on Friday at 2,628 to 985, or 73% for joining the UAW.

The landslide win will make the Chattanooga factory the first auto plant in the South to unionize via election since the 1940s and the first foreign-owned auto plant in the South to do so.

It is also a huge shot in the arm for UAW President Shawn Fain's campaign to unionize plants owned by more than a dozen automakers across the U.S., including Tesla. Fain, known for his aggressive bargaining tactics, and his team have committed to spending $40 million through 2026 on the effort.

Jubilant workers, some in tears, raised their arms in victory and held aloft "Union Yes" posters as the final tally came in.

"I'm exhilarated that we actually accomplished what we set out to accomplish," said VW employee Lisa Elliott as she hugged her coworkers. "Tell Mercedes they're next," she cheered.

A Mercedes plant in Alabama, at which a majority of workers have signed cards indicating they support unionization, will be the next facility to hold a UAW election, during the week of May 13.

"You all have just done the most important thing a working class person can do, and that is stand up," Fain told workers at the count watch party.

"You guys will lead the way. We will carry this fight on to Mercedes and everywhere else," he added.

Although the UAW narrowly lost votes at the same plant in 2014 and 2019, this year's vote was preceded by surging public support for unions and successful contract negotiations last year with the Big Three automakers.

"The margin is overwhelming," said Harley Shaiken, professor of labor at the University of California, Berkeley. "This is a historic moment."

VW took a neutral position on the vote at its only non-union factory globally. The UAW has previously represented VW workers at a Pennsylvania plant that built Rabbit cars before it closed in 1988.

The UAW - which has seen its membership fall as Detroit automakers restructured - has for decades struck out at southern auto plants, where anti-union sentiment has long been entrenched. Earlier this week Republican governors in six southern states including Tennessee spoke out in opposition to the union drive.

In addition to the two narrow losses at VW previously, the UAW sustained three more significant misses at southern factories owned by Nissan, the last in 2017 in Mississippi.

But the broader labor movement has since gone through somewhat of a renaissance, with a record number of workers across various industries going on strike last year.

Last autumn U.S. President Joe Biden walked picket lines outside Detroit, where the union scored double-digit percentage raises as well as cost-of-living increases from General Motors, Ford Motor and Stellantis. That sparked a wave of hikes by non-union automakers that some analysts said were designed to keep out unions.

Biden rebuked the Republican governors after the vote, citing several union victories in recent months.

"These union wins have helped raise wages and demonstrate once again that the middle-class built America and that unions are still building and expanding the middle class for all workers," he said in a statement.

In addition to the Mercedes plant, the UAW has said that more than 30% of employees at a Hyundai plant in Alabama and at a Missouri Toyota auto parts factory have signed cards indicating they want to join the UAW.

Pro-union workers at the VW plant say they have campaigned to secure improved safety on the job, better work-life balance and improved benefits.

"Now that it's official I can relax," said Robert Crump, who has worked at VW for 12 years, and voted yes in all three union elections. "It's a really good feeling."