Major League Soccer's all-star victory over Mexico's Liga MX best on penalty kicks in Los Angeles last summer was so compelling, both sides agreed to do it all over again Wednesday at Allianz Field.

The relationship between North America's two biggest pro soccer leagues only recently has grown into a real rivalry. Until then, it hadn't done so because of Mexico's dominance in whatever international competition the two leagues engaged.

Three months ago, the Seattle Sounders had a breakthrough victory over Liga MX's UNAM in the Concacaf Champions League final, which ended a 14-year winning streak by Mexican teams.

MLS All-Star and Loons coach Adrian Heath was an outsider looking in when he arrived from England to the United States in 2008. He has seen the evolution.

"This is the closest MLS has ever been to Liga MX," Heath said. "When I arrived, the gap was pretty big."

Heath credits "the incredible investment" made in his league and its clubs while he has watched MLS grow from 14 teams and next season will add its 29th, in St. Louis.

"Long-term, this will be good for Liga MX as well," Heath said. "The U.S. is getting closer. Our league is getting better, buying more players, competing for the same players to buy. I think it's only good for the competition."

Last week, 71,000 fans filled Los Angeles' SoFi Stadium for a Leagues Cup Showcase doubleheader in which LA Galaxy defeated Liga MX's Guadalajara de Chivas 2-0 and Los Angeles FC lost to Club America on penalty kicks.

Liga MX has history on its side, having been founded in 1943. MLS made its debut with 10 teams in 1996, two years after the World Cup was played in the United States for the first time.

Despite its growth in soccer's vast international marketplace for players, you might have a hard time finding a fervent Liga MX fan who'd agree MLS has caught up.

"It is clear that MLS has grown a lot," Liga MX coach Diego Cocca said in Spanish translated by MLS. "The Mexican league has always been a very strong league. Coming to play in these kinds of games makes both leagues grow and want to improve."

MLS builds momentum

LA Galaxy star Chicharito was born in Guadalajara and began his professional career there before he played for Manchester United, Real Madrid and elsewhere in Europe until he arrived in MLS in 2020.

He'll play against his countrymen on Wednesday as the MLS All-Star team captain chosen by a vote on Twitter.

He calls meeting Mexico a "very surreal situation" in which he is playing his part with that "gap" Heath refers to narrowing. Chicharito was asked Monday what it will take to convince Mexico fans and fans worldwide someday soon that the gap is closed.

He noted the United States' 2-0 victory — the famous or infamous "dos a cero" game — over Mexico in a 2002 World Cup round of 16 game as the moment between national teams that helped turn the tide.

"MLS wasn't even as big then as it is now," he said. "It's going to take time and patience. Growth takes time to develop and it takes time to accept in the minds of a lot of people. That's evolution.

"You need to adapt and accept that competition makes you better. You don't need to be threatened by it. You need to feel it's something that makes you better and better and better. We need to take the best out of each league."

MLS and Liga MX executives decided one year between the teams in Los Angeles wasn't enough, so they scheduled a rematch.

Rivalry's 'great future'

MLS Commissioner Don Garber indicated there might not be a third time between the leagues in next summer's MLS All-Star Game scheduled for Washington, D.C.

"Now that we will have our Leagues Cup, I'm not sure we need the All-Star Game to be another aspect of our [MLS-Liga MX] showcase," Garber said. "We'll think about what the next opponent is. No decision as yet whether it's Mexico."

Nashville SC defender Walker Zimmerman called last year's game "very competitive" and "not something you see all the time" in an All-Star Game.

"Having it in L.A., the fans were all behind it," Zimmerman said. "It was passionate and we won in a PK shootout. So now we're looking to run it back."

Guadalajara forward Alexis Vega reminds what Wednesday's game is before the leagues meet again on a more meaningful occasion.

"From my point of view, it is a game to enjoy," he said in Spanish through a translator. "It is a game to provide a good show to the fans. Later we will see how many times MLS and Liga MX teams will face each other in maximum tournaments.

"In an official tournament, I do see it as a parameter to see what the two leagues are made of."

For now, this All-Star rematch is about collaboration as much as competition.

"I think we will have a great future with that league," Garber said. "We just want to collaborate on so many different things. Our two countries have enormous opportunity to continue to embrace each other's cultures and build this sport together."